WildFurbearerManagement and C onservationinNorthAmerica

Edited by: Nlilan Novak

Ju-es A. BakerMartyn E. ObbardBruce Nlalloch

Ministfy Of Vincent G. Kerrio- Minister

Nat u ral

Resources@Ontario

51ANAIOMY AND PHYSIOLOGY OF FUR GRO\VTH:THE PELAGE PRIMING PROCESS

GRAHAM A. J. WORTHY Departrncnt of Zoology-,University of Guclph, G.uelph, Ontario NIG 2\'Vl'JACK R()SE, Department of Animal Science, Oregon State Universitl', Corvallis, OR 97331FREDRICK SToRMSHAK, Departmcnt of Anirnal Science, ()regon State Llniversity; Corvallis, OR 97331

IIail is tlre rrrost t:orrslrictr<lus chirr-ircterristic ol'tt--t'rcstrial tnatn-rnals, perfirr-rnirrg u vai'ic'tl of firncti<.rrts suclt as prolcctivc colora-liorr, carrroullacc, clefcnse (e.g-.. thc-- spittcs of heclgelrogs

IF.rirraccicl:ic] ol porcupines lllrcthizott dor.sutuntl). sextral displar.ancl (a<:rile sensitivitt (l'ilrlirrg ancl Hale 1970). Rv lzir lhc- nrostinrporfturt firnction of hair is thelrnorcgtrl:rtiott, :tncl, itt utattvspecies, chnnqcs in length artcl clttrsilr' of pelage (hail ol firr)()ccur sc?lsoll2llll' kr pxx idc uppnrpliate ittsttlatiort.

\{uch has bectr publishccl on the gxxltlt atrd t'cpl:rt:ctletrt of'hair in hurnans ancl in clorrresticr irtrcl labot'atot-\'anittt:tls, lrtrt Iclstudics have been clottc otr t hc hair gr<xvth ol rvild lirrbcat'ct's. I'ar-ticulalll' lackirrg :u'c slrrclie s on the acl:tptir c rrrlc of pe lage atrcl ortthe prirrrine of Pclage. lt is uls() ilnp()rlant to relate elI\ itrrtttrt(tt'tal (i.c., liuht, temperirtutc, nrrlt'ition) ancl phvsiological <:t)ttcli'

1i()ns not orrlr' 1o thc cxtct'nallv visiblc t:ltirtrgcs lrttt also to thcsrrbcutarreous activitv that ultirrrirtcly nr:itrifbsts itself irr tlrc rrtolt:rncl gtrrlth of nerr liair.'flrt tr:rlut-t'autl tittt:rtq.t lltcsc srtltsttt"f:rce lersponscs r)rust l)e knorvrr if <arrst---ancl'eflect telatiotrshipsinr,olving- cnvilonmerrtal iurrl aclaPtivc fitctors :ttc to bc ttncler'stoocl. 'l his chaptel u ill clist:rtss the anatotttical antl phvsiolouit:alt:h:urgcs that occut clirringi the flr gtrxllh <:r'clc aucl lill lclatc'these to thc "yrrirnine" of frrr-. Ilc--r::ursc thct'e have bccrt f cl sttttlie s

irlrrlvinq rvilcl aninnls, sorttc infirrtnatiort ott huil rrill lrc clralrtfrrrrn rescar-clr r:ortchrclccl otr ckrntestic artrl laltot':rton'anitttals.

HAIR STRUC'I'URE AND FUNC'TIONKntxvlcdgc of' tht: origirr ol llril is linriteci: lt<tucvc't, the firre'l'unncls of hair folliclcs arc llow thortglrt t<t hirvc cr'olvecl firrrrtcpicle r-nral thickcninqs (prototrichc's) that per-firt tttc'rl :r

mechanoscnsor'1, lirnctiorr irt ltti<cslt'al tnantutitls (Ling l1)70).

l)r-ototri<:hcs gave r-isc t() scns()r'\' pits benvccrt thc irttlrr-ic:tteclscalcs of lheser reptilclikt-- rttitttnnitls, iuttl prcscnt'da1' hair lollit:lc--s

ot nrarrrrrrals errrlrcrl firrtr thesc 1;its. Prirnitive hair' probabhplavecl it sells(t \ fittrctiott: being u'cll supplietl l ith nc-n cs, it stillstrbscn'cs this lirnctiorr toclu\.-l'hc contrilrutiorr ol'hair to tlre crrr-Irrlion <lf h<lrneothctrtrt is contrrrt'etsi:tl. Flou'cvet, accotclirtg ltr

fohnsorr (1977), rr'ithotrt suclr a clc-r'icc for conset'r'itrg hcat it is

rrnlikclr,(hat horneotlrclrrtr irt rtt:tttturals cortl<l hnrt-- er<rlvecl.

I l'rc.cnt arLhc,': l.orrg \l.Lrrnc l.,rlr,rrrr,rr, ( Iriicr.irr ,,1 ( rriilorrrirr. l(10 Sh.t11i'' R(),r11.\'rrrr,r( .fu/. ( i,\ 1):n)(ll).

Hair Structural AnatomyIlair is kerlatinizccl qtrrss libel plochrcetl lx tlre ltlril firlliclc. ttrrcl

irr corrrbittalion rvith its utt2rcllc(l sebltceotts glancl firrrtts tlret Pilo's(lr:r<cous r.rrrit (\krntagna anrl Vurr Sc()t( l1)58. Nlorrtagtra attcl

P:rlakkal l1)7 1) (Iiigs. l, 2). lSitsicalll l\t() tvl)es ol lrair'llbcrs corr-

stituto thc lrclaee of ttuuttttt:tls: ovcrltait s ltrtcl rttrtlcrltitirs (Dttn'

lilth l{)25, l'lblirrg- ancl Ilalc l1)70, Lirru l1)70). ()rellrrtit's, alsrr

callccl lriurtrl hait's. grrlt tirrrrt Pt'intarr lirlliclc's, rt'hct'elts ttttcl<''

rtails (rrnclc'r'firr) grixv lirrrtt setortclalr folliclcs (\\'akc l1)71)).

HYPOOERMIS

Fig. 1. Generalized diagram of hair and associated epidermal derivatives in

mammalian skin.

SEBACEOUS ..

82S \\'ilcl l"urbearer' \lanagelnent ancl ( lonscr-rati()n in North Arncrica -Ihe Pelt arrd the lur lnclustn

SEBACEOUSGLAND

Fz2

tr

FzzzE

ARRECTOFPILI MUSCLE

MEDULLACORTEXCUTICLEOUTEF FOOT SHEATH

|NNEF fROOr -lSHEATH L

CUTICLE

HUXLEY'S LAYER

HENLE'S LAYEF

BASAL LAMINA/l

FIBROBLAST

MELANOCYTE

DERMAL PAPILLA

CRITICAL LEVEL

Fig. 2. Detailed diagramof the hair. Source: Montagnaand Parakkal (1974).

l)olrrick ( l1).lf)a. l1)(il) cl:Lssillc'rI rlrc llril ttpcs ol rrrirrk (,\lt,r1r,1a

zrl.rort) rts grtet rl hlrit s. irrterntt'tliltl<' r.lrnr'<l hlrit's. arrrl rrrr<lclfirr. tlrcrrrajor' <lilfclerrcc lrt'ing tlurt irrtelrrrerlilrte grrer'<l h:rils ntlt'sliglrtlr sh()l't('l tllrrr g'rr:u'rl h:rit s.

l)t'irrnr-r firlliclcs an' rrsrurllr lrccorrrlr:rnit'rl lrr sc'lxrteorrsgl:rrrrls. il s\\clrl qlenrl.:rnrl lln lulcct()r ytili rtrLrstk'. nltclelrs tlrcsctotttl:Lrr firllicle ustrallr It:rs orrlr s<llrceoLts glenrls :rssocilttetl\rith il. l li(' plirrr:u r' lirlliclcs of nr:rrrr spc't ic's ulc :rr-r-:rnqt'rl in lr

1r-io patlcln (r't'nlr':rl l)lus t\r() lute ruls) th:rl lrccorrrcs ussociatt'rllitlr tlrc'lirtcr'-li)r'nrine scconclrur Iirlliclcs (l)olnick l1)51)a, l1)(jl.l{r<lcr-ancl Slc'plrc'rrsorr l!)(ilJ. \\':rkc l{)71)). Sorrrc rrrarlnrals, lrou.crer. srrtlr rrs tlre trru'(lilt.s lttttrtr.s) lurcl lrorse (liqutL.s cufutllrt.s),lt'areno lirllicrrllrl srrlrpirre'. an<l tht'lirlliclt's ulc clistr-ilntecl evt'nlrllnort,tll( )ltl rlrr' :kiir.

IJust'rl on stu(lics \\'itll sltecp (()r,i.r raizr). sc't'orrcllur lirllicles:rl)l)cllr'1o lrt'of 1\\1) l\ lx's (l l:rrrlr urrtl l,r nc l1)5(i. Lt nt' l{)ti{i). Iirl-liclt's o{ tlrc flr-st tvl)e :rr-isc llrrnr l}rt' 1i'tlrl cpitlclntis. As tlrc fi'trrl('l)i(l('nr)i\ lrr'<orrrt's kcllrtinizerl. n() t)('\\ Iirllitk's ol tlris trpe elcg('n('r'ilt('(1. I'irlliclcs ol th<'s<'t'orrtl t\l)c 1()r-nl us ll:rnclrt's ol llrc( )l'iei l):ll ( l ilst tr pc) li rll icles an(l n (' r't'{i'r'r'c'rl to lrs cleliverl fi rll iclt's{l"ig.:t). lo{.lctlrt'r'tlrc lllst rrrrrl sctorrc[ tr1>t:s of lirllit]t's lilrrr ir

t ottrporrrrrl lr:rir firllit lt'. tlrt' Iilrc'r's ol rvlriclr p:rss thrilrqlr :r corr-rttott Ilrir clrrlrl (l"ir.I. il). I Irc nrrnrlrt'r'o1 <lt'r'ivccl Iirlliclcs nl:r\'\':u'\.t:t.,'ti;rllr tst r'Irt l,rrrt.

()rt:tlcl lr:tit's :u'(' ( ():u'\('. r':n ilrltlr r-igirl. :rnrl Pigrrrc'rrtccl. I lrctl'('l)l('s('nl lll('()uter-lrrrrlt'r'lirr'llnc'r'ol tlrc ltcllgt'ol trrosI rrrirnr,rnuls (l,inq l{)70) lLrrrl rt'< civc trrost ol tlrt' :rlrllrsion lirrrrr tlit't'nr i.1()nnl('nt. l lrev ten bc't'r't'< tctl Io irrtr-clrst' tlrt' tlrit'krrcss of tlrc( ():rl :rn(l lLlso lir r rc l ior r to sht'<l u:rl<'r' rll rpk'ts. kecpi nu t Itt' clt'c'1 rc'r'

lirl lrrver'<b-r'(F.bling rrn<l IIlrlc l!)70. l1)8:l). ()rurrrl lurirs urrr<lt'r't'lrp ittlo tltt'spirtcs urrrl (lllills ()f sorrrc irrsettirr'l-(.\. l''{k-nt\.illl(l sl)ill\ :url('lIlcls ('llrclrvglossitla('). 111(' nr:rrrc's of lrolsts :ur<lllrnts \l)attlltrru /r,o). :rntl tlrc'lrlistlcs ol piqs (Sit.r.rriry'lr) (\lorrtugrrurrtttl l):Lr':rkklrl ll)71. \\'lkt' l1)71)). L'rrtlellnirs urt'sltoll. tlrirr.:Lrrrl

Fig. 3. Compound hair follicle, showing primary follicles (central and lateral)andderived folljcles. Secondary epidermalfollicles are produced during uterine devel-opment and are fixed in number. Secondary derived follicles are producedseasonally and are therefore variable in number.

l)ignrentc(1, ancl lcplcscrrt the rnain insrrlelitrg liLrcr'of firr inrn()st nuunlnllls. l'hct el'c tll(' krrrgcl llrirs of htrntans :rrrcl llrc'rrrrol o1 shc'cp (I)rrrrlirrrlr l!)25).

'l lre lrair sh:rli oI grrarrl lurir-s urrcl ulxlcrhairs is r'orrrposccl ofall ()Lrter cuticlc.:r (()rtc\. lrn(l a (entllrl ('or('()l'l)lcdulllt (\l()ll-tusrur urrcl Varr St ott l1)58. \lorrt:tenu all(l l)anrkk:rl l1)71, ()tllutrdl1)tt:l) (f ig. 2).

()tliclt.-'I'lrc tirrrctiorr ol tlrt' < rrliclc is to birrrl tltc (ol't('x,r hich l-orrlcl olhclu isc bct orrre tr-avt'il ol slrlit irrrtl lull apart. It is

lrsingleIlrter-ottranslrrct:nt.rrorrltigrrrcrrte<l tcllsnlrosc'fiecrrrar.gins alc clilcctt'rl outlurcl t()\\'elcl tlr('tip of tlrc ltair'(NIont:rgrlrlurrcl I'ar-ukkal l1)71). '\n ('xccl)ti()ll k) tllis is thc lrolcrrpirre. I'hoscscirlcs (t ells) ule (lir('ct('(l clou nn:rlcl, :r rr olrliou s arluptatiol) ( )f tlrcb:nJrlikc rlrrill (\\':rke l!)71)).,'\ltlrorruh tlrc tuticle is rrsrrallt sinslc.larclc-rl. tlrc irrclir ichral c('lls ar('rrolnr:rllr clorrgutctl srrt h that thcr

l)arliall\ rxc'r'l;rp l itlr rrcighlror-inq cclls to prrrvitle sere r-al lerclsol prrrtectivctuti(lc:rt:lr)\ given poirrt:rkrrrqthchlrir slr:rtt. lrr tcrlilt':ulrlrsis. l ilclliti'rcsc:u'r'h. :urr[ folerrsics it is oficn possilrlt'toirlentitr hails ol uu iorrs species bi thcil clluuctclistic cuti('ul:u's.ulc l)llitt:r-ll (e.u...\rlolj:rrr lLrr<l [(olerroskr l{){i{)). (]rrtirlc cells of'the hair sh:rfi :n't'irrtt'r'lockerl nith cclls of tlre irrrrcr rrrol sht'ath.tlrc lutter- l>eirrq <lin'< tt'<l ckllrrlur-rl tou':rr'<l tltr' hail lrulb (IIon,t:rgrlr urrcl I)llakkel l1)71). I'lris iu lungclll(,llt fllurlr lrrrclrols tlregtrru ittg llril irrsirle tlx' folliclt' (l;iu. 2).

(il1rr.-'l lrc' nlrss of rrrost h:rit's is corrrltosccl of cortt'x, :r t'orrr.

l)il(t uggregutt' ol <c'nrc'rrtcrl. tirsitirlrrr (syrirrtlle-slt:rl)('([),kt'r':rlinizcrl cclls (\lontaqnl

^lt([ \;nr Sc()tt l1)5fi).'l'hc cortcr is

rrrechanit'ellr thc sll()ng('st yr:rrt ol thc heil f iltcr.lrr huils that:ut'l)iqu)cntc(1. n)cllurin glurrules urt eliqnt'rl lorrgiturlinallr \\'ithintlrc cor'1itul (cll\. ln grr:rrrI lr;rils o{ tlrt,ntink, piurnt'rrt i\ ((,llrcr}ll al('(l ilr ( rlls ( l()s('st t() 1h(' rn('(hllllr. leavirrg :r clt':u' yrigrrrcrrt-li eezont'lrc'rtc'rrtlr tlre cuticlc (\\'ilrhrrrrn l!)i l). ltr tlrt'ebst'ncc of pig-nrcrlt,h:lilslrl)l)eultolrcrhrll rr'hitcoltlllllslil(cll1.\':rri:rbk'nrrrrr.lx'r-s of snrall eil syr:u't's clrllctl lirsi :rn'irrlt'r'slrt'r'sr'<l unronq tlrt'

o-

-boi'-

I tI

I'clasc l'rirning . Il?trtlry tl nl. 82!)

cclls of tll(' (()rte\ (llatrsrttan l():')2, l9l l). Ilc'firt't' tltc corlcxlrc< onrcs firllr kclutinizcrl tltese sl)u('('s itl c llllctl l itlr lltricl; :Ls tlrt'hair glons unrl ch'ics out. tlre llrii<l is leplececl br lrir:'l'his phe-r)()rrlcn()r) ltlso t otttr-ilrtttcs to cltartqt's irt colol o{ t}tc'hait'.

,\lultilla.-Iltt: rrrctlulla is t'otnPosetl o{ llrtgt--. looselv cott-nc'ctccl keratirrizerl cclls (Ilorttitsrut ancl Vatr Scott l-()irlJ, \ftrn-taqna urrcl l)alakkal l1)71, Spcalnran l{)77). Itt lut gc'. < oat'sclrlrils it rrrat be corrtirtrrorrs ot' fl-agtttcrttetl. llrt:t't'as irr firreh:rils (rrnclellirr') it is <liscorrtirlrorrs ot' abst:nt. lltc ertctit torvhiclr lririls at'c nreclull:rtccl vrttit--s cortsiclerablr lroth attrongitnrl u-ithin specics. In hrtnratts att(l tttitttr'<llher tttattttttltls thcnrcrhrlle nrar bc otrlv onc or $rrt cclls itr tliatrteter, lirtttiitrq a

tint poltiorr ol thc hail slritli. Ilont'r'cr, the ltilil of trrclctrts, car-rrirrrlcs srr<'h as rrrirrk. arrrl lrtrrsitniarts cottsists ol lalge, r'lrcrto'latcrl (possessirtg an air'tillecl clnitr) nrcclttlla cells hclcl1()gclllel bt lr thin shcath o{ a(n(cx (Nlotttltgttlt atl<l Palakkal107.1. .fohnson M77, Spcarrnan l!)77). Lrrlgc'r' qttarcl hrtir-s ol'rnink attuirr tliatttclct's of l20 prrt, ivith the cliarrrctct ol thtrr)rc(hrlla leaclrirrg 70 pnr ol irfJlii of tlrc slrali (\{ildrrrarr l!)li l).lrr thc titlest yroltions of thcsc libcrs thc trrt:clttlllt is:t tttrrlititt'orrs air'flllecl cllurtlrt-t'. ['ntlcrftrl Iibc'r's ol tnittk itt'c apprrrxi'rnatelv I1-l(i ptri in cliutrretcl lll)d posstl.is ll rrltllr)\\' tttc--clttlla

cornpliscrl ol racuolatctl cc'lls (\\'ilchnurr l!)ir'1). 'l'lic' trtttnbet- of'vucrrolalcrl cells anrl itrtet-ccllrtlul uit sp:tt'c's itr tlte trrcclttll:tqrcatlv afli'ct (ltc shccrt artcl colot lortcs of the lriril lrt iltlltrcttc'irrg tlrc lcflerctiorr artcl alrsor'lrtiorr ol lieht..Johtrsott ittt<lIlonrlx (l()75) also cotrcltt<lc<l tlrtt lr:rils nith larue Illc(ltllllll'\'splrccs ploliclccl it gtt:alt'r'tlcgt-cc o{ irtsttlatiott as a t-esttlt o{ (hc

clltrel)rlt: llt ol lrit'insi<lc thc huil sh:rlt.

Microscopic Anatomy of thc Hair FollicleI'lach hair-tibel clcvcloJrs irr arr irnagin:llccl p()rti()lr ol tlrt-- skinc:rlled the hail firllicle antl is corrtposccl ol hunch-ecls o1'tltottsanclsol cuiclclrn:rl cclls. rrurst ol'u'hich are keratirrizcd ancl cleacl. IIlrir'lirlliclcs alc slarrtecl itrto (ht' clt'rtrtis (Fig. I ) irncl tnav be fouttcl as

clccp:rs lhe subcutlurcotts fultr tissrtc lrtrclcllving tlte skin (hvpo'

clclnris). As u t'csrtlt, hairs ertretgc filri the skirt a1 :rtt lrtrqlc ancl:u'c r.rsuullr clilcctecl tou'alrl tltc lips of tlte itppcndaecs.

'fhc entire firlliclc is sut-t-oltttclctl ll a lnaline or-gl:tsst ttrctl'lrt ltrre calle cl thc basal lartrina (Fiq. 2) ancl lll trirr ot' three l:tttlt's of<'Onnccti!c lissue rrurrlc rrP of collugctrt flbc|s all(l Iil)r(xVtes:rlr':rnqc<l ()rth()q()nall\' (\lontagrra ancl P:u'akkal l{)7-1, ()cllarrd

l1)l3li). Oeltairr s(ren(ls of c<tttttc't:lirc tisstte cells ltlso elotrglttc atlclclifli:rerrtiutc into the slrrooth tnrtstle flbers of'thc artcctot' pilirnusclcs (Irig.2). (lorrtlrction of thesc rttrtsclc's (allscs clc('li()n ()f

tlrc hairs clurirrg {li{rht ancl clisplins ol':rnget. atrtl also iuct-easc:s

thc irrsul:r1ivc' properties <tl thc <:o:rt ll errablittg tnot-e ait lo llt:trappccl be neatlr (K]rrsc ct al. 1977,I'.blinu an<l Hale 19133).

Hair lfulb.-'f h c- hail li rllicle ultiritrs its eleatest diarlrctcr al theb:rse. nhct'c' il is cxpatrclccl itrto a clttlr'sltitpc:cl lrullt of epitlrclilrlcells enclosirrq a cavitv of'krosc conncctivc tisstrc callecl tlrc clct'rrrul papilla (l\lorrtlrgna anrl Varr Sc()tt l1)58). l he clet rtral pap.illaanrl cclls of tlrc hail llrlb ilre sarl)ln ?itc(l firrtrt eaclr othct'ht a ltase-

nrcnt rrrcrnlrtunc (bas:tl llurtitt:r) abotrt 50 prrr thick. Atr int:rgirt.Lr rlirrc ch'enn acr-oss thc rr'itlest cliutrrt'tcl' of lhe clerttt:tl papillarlivirlcs thc llrlb ol tlrt: lirllicle ittt<t tl-o t'ct1i<ttts, tlrc trppcr lrtrllrarrcl rlatrir (l"ig.2). l his arbitlalr scparatiott littc u:is fll'st callcdtlre "criticirl lcvcl" lrr' :\trlrct'(l{)52). [)trlirrq:l(tive hair $rru'1h.cclls bckru' this lcvc'l urt' ttncliflelcrttiltlcrl ancl tlivitlc. Iirllouslrlurrcl LaLrre rrcc (l()ir8) cle nrorrstt atc'cl that irr colccnric['Ireatetlrrricc. euc lr nt:tlt'ix cell cliviclc'cl on< c alrortt evct't I lJ hours.

I lrc rrr:rtrix or gclrttitr:tlion centel (\{ttntaqtta :llt(l lral'akkall1)7'1) uires risc 1o ell cells of tlrc hail shaft (rrrt'chrlla. ('orlex,( uliclc) :rnrl the irrrrt't t'oot shcatlr (ctrticlc, Httxler''s latct, Hcrtlc'slar'<'r'). ( ie lls nl()\e ul) in tows fi'orrr tltc tnalrix to tltt'trppc-r ltat-t o1

thc lrulb. riltc-tc' ther ittctc':Lsc' itr rrllrttrtc- rttttl lrc<'otrre verticall\elonsirt('(l (i\trbcr l!)ir2). l)itlirle rrtirttiort ltcgitrs irt the trppc't pat'tol thc llrlb:ur(l is c()rnl)letecl ut vittiotts sites fllthc-r trlt irt tlreiirllicle, clelrcrtrlirtu orr u'lticlt ('()rlll)oller)l is lrcinq firl'ntetl (N{orl'

taqnu uttcl I'arakkul l1)71). Kct-atiltizatiotr ol the cottc'r iitrclnrecltrll:r of thc luril is rtsrtallv cotnplctccl approxitrrlttc'lr'()nc'lhirclof tlrt'u'av beluct'tt thc tip of tlrc p:rpille atrcl thc strt'l:ttc of tlre

skirr, u itlr tlrc ctrlit lc becorrrirrg kct'atilrizccl in the firral ()nc-lhir(l(\Iorrtuuna :rnrl Varr Scott l9ri8, Nlontaella irrrcl l):rlakkal l!)7-1)

(Fiu.2). NIalrtt'e huirs alrorc thc kcratogett()tls r()llc shou'tto ciis-

tinct t:cllular ele rrtcttls (\lontauna attcl Vatt Scotl l1)58). l he hair'{irllicle is also thc sile of or-isirr o{ lr:rit'Pienrents (tliscrrssccl

beltxr').-l'he dernr:rl papilla, u utitss of cottttcctivc' lisstte ertclosccl bt

tfrc hail btrlb cluring tlrc activc'lv qrttrvitt{ plr:tsc (ana{ctt) ol t}rehair tr,r'lc, is attaclrccl (o thc <onnective tissttc shcath axlttrcl tltt'firllicle lrv thc rtatlxv papilla stalk (Fig. 2).'l'hc size of thc (lclrnalyrapilla is closclv t'orrelatecl n'ith thc size of the firlliclc ancl hairassoc:i:rtt--cl u ith it: firllicles prrrclut'irtg lar-ge hairs lllc larqc bltlbsancl clclnral papillac iitrcl vice versa (St:lrirrckcl l{)(il). Hair-s l'ithrDO|er thiur Ottc tncclulla haYe :r tlistallr sltlit dcrrttal papilllr tliath:ts irs nuinv apices as thcrc at'e nreclulluc (\lotrlaeua atrclltarakkal l!)7'1). Iirn'thennor-e, rvltc-tr turr hliirs occttt- itt tltc satlefirlliclc- thclc ale also trio tlct ttuil papillae prcscril (f ittkus l!)51 ).Srr< li closc cor-r-elalioti bclrvcctt the ntttttbct'ttf'hairs attcl subclivi'sions of thc tlclrn:rl papilla witlrin ir sinqlc firllicle sr.lggcsls thatt-at'h krbe of'thc papilla rnust ill(lucc- thc fortnatiorr ol :r hait'firrttt:l c()lnrr)()n rri:rtlix. Altlrougll thc r)rc( hanistrt rettutitts alt t'tti{ttlt,thc- c-r'iclence is ovctu'hc'ltning tllat the clctttr:rl papilla plavs art

incluctive r-olc iti tltc firrnratiorr o{ hail Iirllicles lrrrcl hitit tl't'ou'tlldrrring cniblr<rlogical clevckrpnrcnt ancl eaclr stttcccclitrq hait'qlou'th ot'lc (()liver 196(j, llxi7, l{)70, 1980, Kollrtt' ll)70).

'I he rnost llur)ul'ous cells rvithirr tltc clctlral papilllr ltt c llbt'o'blasts (()cllzrncl l1)lJ3). Also betu'cctt the cellulul cotnpottctrts rtfthe papilla is a protcin-polt'saccharitie qtrttttrcl sttbstattce,tlrrrlrqh rvhich floirt nrrttrct'orts collager) f il)crs.

Inrur llut .Slralh.-Sun-<)un(lirlg thc hair sh:tft fionr thcnratrir to thc openirrg ol tltc sc-ba<eotts qlancl clttc( is the irtlterroot sheath, corrsistine of the cuticlc, IIrrxlcr''s luter. uttrl Ilcnle'slar,er'(F ig. 2).'fhc rnairr firrrcliotr of thc innet-trtot shc':rth trtav bcto shulrt- ()r ( ont()Llr thc hair shafi.Ilecartse it is tht- fl'st firllicular'struclilre to becortrc' kclatinizecl, it lirrlrs the ()r.lter lrottttclanthlough rr lriclr thc tlcvelopirrg hltir is ftrnnt:lecl clttlirtg its firlrrta-tion (\lorrt:rqna anrl I':rlukk:rl l{)7-1).

'l he cuticlt', Ilttxlo's lavet.arrcl Ilt-nltrs laver ule ptorlrrtt'tl lx tlte ttt<nc pcril)heral c()rrccll-tlit rorvs ()f tll(i r)):itrix (\krtttaurtit atrcl Vatr Scott l{)irS). -l'hc

seolrence of cvcrtts inrrrlvecl in the clilit'r'cnlialion oi trt:ttt ix ccllsirrtir the irrrrcl rrrot sheutlr is viltrutllr iclerntit'al lirt-ull tlrtcc <otl'I)()lrclrtsi it is thc r-ate ol changt'tltat sets tllelll lll)arl. l hc firrttra'tion of'1he tlrrce lavt--rs of the itrtrel trr<tt sht--ath begirrs n'ithHcnlcjslurcrtlrrlvatrtcstoIIuxlt'r''sl:tr<'t',atrtlenclsuitlrtltt'ttrtitltr(l'arakkal ll)(i{). \lorrt:rgnir :trr(l I):Irakkal l!}7 1).

-fltt' peltt'rtt ofke|lrtinizetion ot tlrcsc' s:un(' structut-cs is sliulttlr clifl'ererrt: itlrcgins irr Hcrrit"s lart:t, PI-oceecls to tltc ctrlitlc, atrtl errtls irt Iltrr'ler's lavt'r (l'alakkal l1)0-(), \lontuerut urrtl Pat:rkkal l()7-1. ()clllrrrcl

l!)8ll). As eut lr l:nc't' firnns. lil:trrrcnts :rl)cl lri( ll()ltvrtlitt gt rtnttlt'sclevelop irrsirlc'thc cells, tir-st in Ilcnlcs lavet-, tlrett irr thc ttttitle.lurrcl {inallv in Hurlcr's larct'..'\t lltis Lroirtt cach lx\'(rr hrts becttIlansfirrnrerl irrto u ltat'clcnt'<l or-kclirtirrizc<l shcatlr ultrrst ittttr'rral stnrctrrlc :ll)lx'ars to bc <lct'irccl firrnr tlre Iilrtrttcttls atttlcnliu-girrg tlit hollalitte g'r':ttttrlcs (( )<llarr<l l9itll).

'['lrt'crrticle ot the irrrtct trrol shcallt is:ultlogotts lo lhat ot tlrthlril shaft ex( el)t tlllrt thc tx crlappirtg sciLles. rvitlr their fiec rttltt'uins, ar-e rlilcctcrl toxet'tl the lrottottt o{ thc Iollicle. As ttte tttiottc'clalrovc. thc crrlit'lc of the h:ril shrt{i anrl 1hc irtttel tool slrt':tth arcintcr(ligit:ltc(1. urrclrolirrg thc hair rtitlrirr tlrc lolliclc. (lt'lls o1

Huxler''s l:rrc'r'utrrriclc a firrtctiotr utlclitiorr:rl to that ()f strr.l(ttllitlsr.ll)l)()r'1. Soniri ol thc cells o{ 1lris l:rct'tlo not clcrclttp tliclio'lnirlinc qlenules (becorrtc kc'r'atinizecl) :tttcl t ctnltitt alirt': thesecells serrcl llrtr-t':tl cvloplasrttic ptrrt'csst's:l(ross Ilcrrlc's lavet-lttrtlpcnctl rrlc :rs t:rr as tllc ()ilt('r' sltcelh. l hus, thcst' cclls serre lts lir-ing bli<lges acrrrss tltc'rlc'ucl Hettle's luver: atrcl ell ttrtttitttls ot'cner{r's()ul('('s <ottring t() the llltil trrot ltrttrt tlte otrlct'sllcatlttr-ure l lr thc'sc briclges (\lorrt:rgtte etrtl Van Scolt l1)riJ).

Bct arrsc tlre huil sh:r1t anrl inller 11)()l sltt'ltth at'e irrletlockcrl.l)()tll stnl('tul('s r)lr.rst q11)\\'ltttcl ttttnc ttprt'artl at:t1rpt'oxitllatclrtlrcsiurrcr':rlc. lhisrrrc:urstl)at1lx'oulcrsitleotlIcrrltrslltyer-slitlt'sagainsl lht' oul('r r)()l sllcal ll, trsttallr t ottsitleletl l() 1,(' \l.ll i"lt.ll \.

Iiru'lhcrnror-e, cells of Ilt'nlcrs latcr-lrctotttc kcllrlinizcrl intrrtccli-att'lr':rs tlrcv lu isc lirrtr thc nlttt-ir urrtl sliclc'c-esilv agaitrsl tlrc plrt'

830 \\rild I urbearer N{anagement and Clonservation in North America o 'I he Pelt zrnd the Fur lndustrt'

tially keratirrized axi:rl cclls of lhc outel sheath (\'Iontasna arrcl

Van Scott 195t1).'Ihe inncr root sheath is continuously'exlbliated (shecl) ancl

rlisdrarged insicle the pilosebaceous canal at thc lc.vcl of thc seb:r-

ccous glancl (l'arakkal l9{i9). Thc ttrcchanism bl rvhich this pro-cess occrlrs is unknorvn, but it is thought to ()ccul' tin-oughsclcctivc enzl,rnatic desl'adatiorr (N{ont:rena and Van Scott 195ft).

(htter lilnt SlLeril,.-The outcrm()st laver of the hair firllicle, the()uter l'oot shcath, is basii:ally sirnilar in prolifelzrtion, keratiniza'tion, zrncl exf<rliation to the epiclerrnis of'thc skin (Nlontagna andParakkal 1974). 'Ihe olrter she:rth is onl,v one ()f t$() cell-layersthick surrounding thc hair bulb; the inner cells are greatll' flat-ter)cd, whcrcas the outer'()nes are sliehth.'elongated. A short clis'tance above the bulb the shcath develops into tlrree cell-lii1'crs.()nc-third of the way up the fbllicle, thc she:rth bccomcs tnzrnl'-lavcrccl ancl attrrills its sreatest thickncss. Thcre the tall columnarcells at the ()utel pcriphcrv :rrc orientecl perperrclicular-lv to theaxis of thc fcrllicle. As thel' gnxu cetttripetallv thcy bccorneini:rcasingll'flattenecl:rlong the axis of thc follicle arrcl are cuboi-clal in the upper one-thilcl ol- thc follicle. Iirom the level of thesebaceous glancl and abor,c, lhc ()utt:r l'(x)t sheath is inclistin!i-uish-ablc liorn thc epiclerrnis ol the skin (-\'{ontagna and Van Scott1958).

'l'he outer roc.rt shcath \\':rs ollce thought to be u strtiL struc-ture, pnx icling supp(n't firr tl'rc rest of the hair firllicle, but i1 is norvknou'n 1o havc rnole cll'namic firrrctions. In housc tnicc (il{ur rzr.r'rrrlzrs) ancl Nler-irxr sheep, the outcr r'(x)t sl'reath has been obser-r'ecl

to move up rvith thc inncr root sheath ancl be clischarsed sirttulta-rreously into thc pilosebaceous canal (-\{orrtagtrt and Palakkal197.1).'l'here is also eviclcn<:c of cell lnovenlent torv:rrtl the irtncrll)ot sheatll in hunran hails. ancl it is conceivable that thc innersheath is dctivccl both fionr the rrr:rtrir cells of thc bulb ancl the()ulcr r'()()t sheath (Spearnian l{)77). In those species n,it}tcrinrpecl or curlv h:rirs, cach hair follicle cun'es.just irbove thcbulb. -fhc ou(cr root sheath of such tollicles is thickcr on one sicle

than thc other', r,hich ptrbabll'causcs thc curvirture of the fiber1.\rrlrcr l'lli2,1.

(lclls of the outer nrot sheath arc clerivcd largelv fnnn the hairlrtrlb. Horvever-, alter thc lti'.ir rcar:hcs its rn:rxitnuur lerrgth, cellprrrliferation becorrrcs shiicd fiom the bulb to the gernrinal lal'crsittratcrl in thc-- or.rtc|rrx)st la,ver of the sheath (Spca|nrail 11f77,).-fhc gcnninal lal'er of cells is crotrtinuor.ts rvith the basal lanrirta ot'thc iirllicular c:rnal and srrrfacc cpicler-rnis (! is. 2).

Hair (lolor'l'hc disting;uishins color- of rnanrnr:rliatt hurir' :rrtcl skin is cluc t<r

pi{rnents, ref'elr-ecl to lrs rnel:uriris. Speciirlizcd cells callednrel:rrroc\'(cs sr ntlresizc rrrclanin in rnclanosornes ancl then trans-ii'r' thc pignrcntccl rnclanosomc (rnelanin granule) t() tlle sur-rrrunding; cells of the hair:rncl skirr. Arr in-cleptlr rliscussion of thebiocherrristlr, of rnelanin slnthcsis is bcxrnd the scope of thischantcr'. but the interestecl re:rcler is retin'ccl to a rcvie'w of thissubfcr:t bl l':nvelek arrd Kiirrrer (19tt2). Rriclll; nrelanin consists ofscr,elal inter-rnediate cornpouncls alisinq fr'orn the initial oxicla-tiorr ot thc iurrirro acid l1'rosine bl the enzl'me ttrosirrase. Slnthc-sis ol rnclanin irncl its transfer out ril the rnelarrocvtc is bclicvc-cl t<r

bc stirnulatecl bv the clirect acti<xr ol-rriclanocrlc-stinul:rting hor-rnone, which is a prrrlcin scclctccl by thc pituitarl g;larid. Howevet,it is likclv (hat other hormones are also inr,olvcd in rcuulalingrnelanin slrrthesis, espcciallv in thosc spccies that grorl'colorerisllrllnler hail but har,c :rn unpigmentecl (l'hite) rvirrter pelagc. Inthese spccics thclc is sorne suggestion that mel:rtotrin, a ltornrotrcseclc(ccl bv thc pineal glancl, mal act ort rrtel:rrtocvtcs t(, acti\atcan intlacellular "blockirrc IucttlrJ' that inhibits the conversion ofcertain irrternrccliatcs in thc pathwa\'of melanin svlltllesis. -fhc

|csult of this inhibition is the sr-ori tlr ol'u'hitc hair'.l,ocatccl bct'tveert thc tlt't-tlul plrlrillrr rtltrI rrplrtt part of lhc:

lilrir lxrllr :rre rnclanin-protlucitrg urelntroct tcs (\Iontagrta zrtlcl

Vrrn Scott 1!)ir8, Straile lg(jl, Nlontautta atrcl l'ar-akkal l1)7'1).

Nlclanoct tes havc exlettsions, called clcttclt'iles, rvhich llrotmclelll1r()ng tllc lxcsulllptirc cclls ()i tllc c(t'tcx atlcl tncclulla in thtlrrpyrer lrulb. Nlelarrin qranules Iilrcratccl liorrt thc cletlrlt-ites :rrc

takcn u1.r br, lhcsc prcsllr)rptivc t:clls as thev nrole upl'arcl ti<nrthc mirtlix. Once incorporatecl into the hair cells, urelurrin (piu-rnent) carlnot bc u'ithd|arvn; :rnv subsecluent color chanqes thatoccur are clue lo fading ancl neatherinlr (l'lblinu arrcl I lale l!)til3).

'l'he extent to rvl-rich the melanocyte rlerrclritcs l)cnclr'alc tll('hair bulb call g'r'eath.' ittflucrtcc thc tlistt il rrrti,,n (

'f piqlnL-nl arxlthe subsccltrcnt color of thc hair: l)ulinq rapicl hair- !:rro\rth ()l'lrlack rabbits (Oryttohgls t:ttrticulas) ancl rrrice the clerrch ites erxterrrlthrough tlre rnecluila ancl coltcx srrch that both slnrctl n-cs arr' pirl-rncntcd (Straile 1964). As hail g;rrxvth ceases the rtenclrites rvith-clral, until cvcntually most of the piument is deliveretl to tlrcsingle layer of difl'erentiating nreclulla cells overh irrg tlre tlet rrurl

papilla, leaving the linal one-thir'(l ol'thc lrair g'a1 (Strailc l9[i-1).-fhese obsen'ations irrc irnportzrnt bccilrsc it is p<lssiblc thiit cnvi'lonrncnl.al, genetic, ol nutritionnl fuctors mav irrfluence thecxtension of these clenrlrites and tltelebv aili:ct thc cokrt tonc olthe hirir: Furthcr rcscarch is nccdccl ()n thc f:rctors that aflecthair color'.

(ieneralll' therc is little or no pigrrrcnt lilurtl irr the rrratlix,Itair cuticle, ()r the innel'ancl outer lo()t slleatlls. -fhclc

is a shalpclivision betrveen cells ot the hair propel that 2u c pigrncntccl arrcl

those ot neiglrl)ofine stl'uctul cs that arc not. Althorrqh tlicr' pcr.haps clo not con(ribu(c to hzrir cokrr, clcnch'itic nrelanocvtes havcbccn cle tected in the outer root sheatll arrtl everr in thc'rrratlicr:s o1'

humans ancl other nrirnrrnals (\Iont:rgrra ancl Parakkal l1)7.1).

N'lclanin svnthesis ancl gr'orvth of the nreclulla stop tosethertorvalcl the errd of thc hair g'ou,th t't't lc, lcaving (hc last sesmentof qlon'ing h:rir rvhitc ancl nonrncclulLrlccl.

'I'he Insulative Function of HairAlthough hair- sen,es a varietl' ol- {unctiotts. its prinritlv rrrlc is as

an insulating and thcrmolegulatinu nraterial. Scasonal Pclagechlrngcs, rvhich are thought to be prrrxirttallv stinmlatetl bv ern i-xrnnrcntal firctors other th:ur tr--rnirclattlrc, lntlst ultirrratclr lrt'rrxrclulatecl bv clirnate lirl ant'sut-r'ival value to be lcali,,ctl (l.inlr1972). Not surprisirrgll! thcrc:rt'e substatttial seitsonal clltttgt--s ittthe fur iusulat ion olrnosl :r|ctic aDtl terrrpclr alc llt2uriltr:rls, tDainlrrelating to changcs in fur clepth artcl dcnsilr' (Hart 105(i). l hese

f-actors ale also ofspecific inlcrcst t() the fur inchrstlr, r'itlr pt:ltsthat are the lonqest ancl clensest invariirbly lravirtg thc- grcalcstyalue.

Scasonal changes in the coirt irllcct not otrlv thc sizc ancl colttt'of hairs but also the absolute trutnbct'o1'utrclet-hait-s. Llrrdetrlltit'sare lrlore nllnletous dulinq n'inlet'Ihirn sulrlllrer as it rcsttlt tll'changes in thc nurrtbct s of clclivecl firllicles (Rougcot ct al. l-()8'1a).

ln contrasl to lhc norlnal hair clcle, irr whiclr ut lcasl ollc hair isahv:r1's prcsent in a firllicle, clelivccl Iirlliclcs rcgrcss to tlte Ititir'qclm stage or tlisappcar cntirch'clut'ing sumner (Rott{cot ct lrl.l9l3-1a).

-fhcsc follicles become active asiritt chu itrg aututln antlc()ntriblltc to lhc increase in hair clensitr:

Irr thc rrrles (Ilicrotus ngrrslis artcl ,\L rrlnogt.slo) not onlr arethc nunrber of hairs per unit iuclr of skin qrcalcr clut-irtt tritttcrthan summeq but all hairs, ancl itr pat'ticular the grtarcl ltails, :tt c

finer clurirrg rl irrter' (Al-Khatccb aucl .f ohtrsott 1()7 1 a, ( lhcrlr lrncl

Vernel l0T5). The flne r,inter c():rt acts us ir goocl insrtlalor, antlthc co:rrser, sp2irser surlnlcl colrt airls in hc-at clissipation. Sinrilur-seasonal cltatrgcs har,e beetr cklcutnetttecl firr Itutttv otltct strtallx)dcnts, ra, ru"ii ,,. firr larger spetirs sutlr :rs thc l-rttrpcan bison(.Bisonlnrutrus), in nhiti thc ch;rngcs in h:rir cliatnetet-attcl tlerrsitr:ue also accornpiuticd bv parallcl changes itt size of srreat glurrcls(Sokolov 1962).

lbr cffcctilc insulation it is inrpottarrt tlrat huils bc kcpt rlrr.Adjaccnt to the firllicle is iirunrl ar scb:ttr--otts elancl that secretes

oily rnatelials irlt() thc firllicle, thelelrv rtaterproolirru tlrc orrtct'hairs. -fhc inrpo|tance ol this \\'atc|l)ilrofltrg bct'ottrcs appxrclilrlrerr, frl' cx:inrplc, rnuskrat ((hulutru zibttlritu.s) Iin' is u'c'ttccl u ithlaurvl sulphate, rvhich results irt tltc aniur:rl r1()t l)cillll al)le t()rrraintain its bodr. tenrpcr'2rtLrrc in t'oltl rvater (.foharrscrr 1962). Asirnilar rcsult cirn bc ob(:rinccl ll lenrovirrlt the I Ialclut'iart qlarrcl.

irn apo<:r'irrc olgzrn krcated behincl the eve.'nlriclr prochr<'t--s a lipirlthat is spr-eacl over the firr surlace (I lallou ll)8'1).

Arr :rrtirrral's tltc--t'rtrlrl itrsr"rl:i(ion aclrtalh c()nsists of tntt tttttt-

832 \Vild Ftrrbearer Mirnagement and (ionservation in North Amcr-ica r 'fhe I'elt and the Fur Industrr

"HAIFGERI/1"

Fig.4 Thehairgrowthcycle(modifiedfromEblingand Johnson1964).(a) Intherestingstagetheclubhairhasthecharacteristicbrushlikeanchoringbase.(b)FollowtngrherestingStage,the..hairgerm,,becomeSmitotica||yactiVeandeXtendsdownwardsthroUghtheskin.(c)Thenew|yformedactiVefol|ic|ebeginstoprodcethenewhalnDu'ringits growth through the skin, the tip olthe new hair is protected by a keratinized dome of inner root sheath. (d) The new hair, which has broken through the protective dome at thelevel ofthe sebaceous gland, is now fullyemerged and the old club hair may be lost atthistime or retained to increase the densityolthe pelt. (e) Aft!r mitoses have ceased, thenew hair is transformed into a club hair and migrates upwards to its resting position in the skin, leaving behind an epithelial strand oi cells. (D This epithelial strano suDse-quently shortens, forming a small protuberance (the next "hair germ") below the club hair Often the old club hair is still present, so the two mav lie side bv side.

sut urorrn(l the hail .,\t the base ot't hc firrrling t'hll) llltir the ()u(cr.

root shclith cerlls clifl'ct'cntiute inlo the firllictrl:rl gc:nrr cells(l'alitkkal l{)70, Scrrcel l1)7(i). nhich are lhc sc]e(l tor rhc ncxt sen-cration of hlrirs nncl. us srrclr, are thc nl()st inrJtortlrrrt c()lltpol)clllof'thc tcl()sen firllicle.

Ilencatir the firllictrlur gerr-rn cclls lic. the clclrn:tl pupilla ancl its:rss()ciated rnelurroct te s. ,,\s the firlliclc shrinks ()l c()ntl-lc(storralcl the sulfircc of the skitr, lhe clernt:rl lta;lilla tnovcs uprvarclrvitl'r it :rncl stavs ilt c()lltact rvith thc gernt cclls.'fhis is probablvrelatccl lo lr gener:rl lcchrction in thickrress ancl an uprtar.cl nrove.ment of the dcrnral laver r>f the skin chrring catagcn.

Thc l:tst stagc of'the catugcn phase in.rrrlvcs the fix.rnatiorr ofthe h:rir club and thc keratinous rootlets that irttacll it to u'hzitever-t'ctrrains of the folliclc (\Iontagn:i ancl l,alakkirl 197-1). Hair clulrcclls are corrsiclclecl to bc rlc--r'ivecl fi<ln cclls of thc <'oltex becnuscrthcr" possess a sirnilzu ultntstnlctilre (l'arakkal 1970) and are thclast cclls of the hair shatt to bc firrrrrecl. As thcse cells bcconrekeratinizccl thet tirrnr blushlike extcnsions irt thc base of thc firlli.cle arrrl interdigitate l-ith thc unkelalinizecl gcrrn r:ells of'thcrouter r()()t sheathl rnodillecl clcsrnosornal 2rltllcl)lneltts betl'eenlhe {\\1) cell trpers tlr-nth irnchor- thc ]ritir- insiclc' t]re firlliclc(P:rrakkal 1970).

felogen'l'he rt--stinq or tclogcrt phasc ot the hair 1111111'15 cvcle is :lttaincdriherr all ccll gr-o$'th, clifli:renti:ttion, uncl rrror,crncrrt ce:rsc :rnclthc frrllv srorvn huir is anclror-erl itr tlre firllicle br, nrcuns of itsclub-shltpecl lolcr cxtrernitr. Sut h fllrcr-s ur-c rclcr-r-ccl to us "clirlrh:rirs" (Nftrntagn:r arncl \ran Scotr 1058, l)arakkal l!)70, \ftrntaenaancl Parakkal 1 97-l, Scngel ll)76, \{:rke 1079. ( )cllancl l trxlt). \\'l rcr r

renervc-cl firllicLrlal uctivin occtrr-s liqairr during anaqcll, the ncn,hrrir eit hcl clisloclqcs ther cirrb hair lrvi ich is thcri sl,ei; or srrxr,s inaloneside it (Nlontaqna and Pruakkal l1)71) (Fies.,1cl, c. f). (ilulrhairs rrray be rctlrirrecl thtrlrgh rnorc_. than orre hair grrrrvth clcle.:rs l'ith sorrre ckrqs, or nrav bc rlisloclqc(l clur-ing each ncl' gro\\.th(Kluue ct :r1. l!177).

'l'hc teloqen tirlliclc is a stal)le stl-uctrlre onlv half to one-thirdthc lerrrgth ot the anaqcn ti rlliclc lNftrrrraqna lncl Parakk:il I974)(l'ig. 1f ). L)ulirrs this Phase thc rler-rral papilla is recluccd to:rsrnall sphcrical nr:rss of t:clls lr.'inq clirecth, ltcneath :rnd in cotrtactx ith thc lirllic le ec'rrrr cells. Stmctrrrcs ancl ccll litver-s charactcr.is-tit: ol the grrllirrg hail firlliclc. suth rts thc ut:rtl.ix, medulla, anclcuticlc ()f tlle hair shafi ancl inncl nrot shcath, are lackins in thetckrgen tollicle. I'hc nrosi pfirmincnt f'eatures of thc r-estinefirllicle are the hair qclrn and the club of the hair shaft (N,Iontagniancl I'arakk:tl 197,1). .\lthorreh the old hair or ltair clrrb ,r-r"rlbcrct:rined thnrgh onc ()r-rn()rc subsequent hair generaliorrs, it isevcntualh' rnoltecl. Rctcntiorr of'club hairs rvitl'rin the folliclesensulcs that thc iinintal rvill hare a cover-ing of hair betrveen tlretinre rrhcn hair qrrxvth stops irrrcl nerv hair ptiduction beqins. F<irthosc species of mamrnals that have one or t\\,o se:rsonal coatcltitttgcs, the teloqen phasc of thc h:tir- qtr)wth clclc lasts rnan!'I irrrcs lorrqcr' I hlrn I Irc :rrrrgerr Plt:rse t l.inq llrTrtr.

PATTERNS AND TIMINGOFPELAGEREPLAC]EMENTHlrir leplacernenl is nonnallv not sl'nt.hr{)llous ovcr the rvholebocll ot a nr:rrnrrral, thrrs arrricling:tny scvere or sudclen change intltermal insulatitxr (lilbling 1965). Hair replacement patterns varvItrrrn spccies to spccies ancl, rvithin a spicies, mal,chanqe ti rrnrnolt to nrolt (Ling 1970). '\ltlxrugh the mrrnber of basic replace-lncnt patterns are srnirll, onll'lt te\\ attelltpts hirve been rnacle t<r

classif '" these sc-cpenccs usirrg st'hernes basecl on thc clirecti<in of'tlre hail errxvth uave (Kr.,ltzor, I{)6.1, Ling 1970). Ling (1970) sue-gcsted flvc basic puttenrs: clorsncl (torvards the back), r'entrad(torvirrds thc verrtmrn), cephalad (torv;rrtls thc hc:rcl), catrclacl(to'nurcls the tail), lrrtl diffirse (no particular pattern). These fivcLr:rsic pirttc-r'rrs rnil be conrbinerl to irrtlicatc the clir-cction of irnr,huir gr'ou,th riavc (l.irrg l{)70). l hc adaptivc value, if arn. of rnoltI):rtterlls is clifljcult to cliscern;ltxrer,cr, it h:rs been sugsested (hatthc rlitftrse p?rttern is the nrost recenllr, evolved (Ling 1970) andtfrat it pt:r-haps irrriicatcs a tropical anccsrrv (L,bling lgti5). Also,

Pelage I'riming r llbrtht et al. tl33

becarrse nralnottrisherd inclivicluals ttttclcrqo this tl'pe of rnolt, ithas been suggested that a dilIrrse Pattcrn mat'itN'ohe :r tninitrtalrnct:rbolic driritt otr the:rrtitnal (Line 1970). Ilorvever, this generirl-ization mal' tto( alu,ll's holcl tnte. Starvirrg irb:rudcitrcd harp seal

(I'hoca goenktrullrzr) pups, l'ather than utrdcr{oitrg ir difluse nlolt,revcrse tlte n<xrnlrl nr()lt pattern irucl retirin the lanugo (fital hair)on theil flippers ((i. \t'ortlrr', pers. obsen':rtion). \Vintcr pelaecdevekrps first and molts last ()n (hc ventral sttt'I:rcel <lf arctic lago-

nrorphs, a potential ltcnefit in the event ofearly sn()w or a Pro-Iongecl rvinter (Ling l!)70). Cauclad aincl cephalacl tnolts mil,v bc:rclvatttageous ttt specics that clcpencl ()ll ease ()f lll()\cltlclltthrough cither heavy vegctatioll ()1'\r2ltel', plrx'icling lln "eten"glain to the pelage :rtrcl (herefirrc reclucittq impedance (Line1070).

C)ne to thrce trtolts per,velrr ltlll\'()ccltl', clepencling on the spe'

cics, lvith the tinring ancl fi'ctpencl'of molts closcll relatccl to tllcspecics' se:rsottal needs. The rettrovirl of ttatut'al selcctiott llrcs'sirrcs fronr dotnesticalecl :rrld lzrboratol'v anitttzrls has probabl-v

disengauccl thesc seasottitl cnvirotrtrtentirl controls fl'orlr their'pelaui cvcles, rcsultitrg in either a cotttitru<ltts cliffirse tnolt or an

irregtrl:rr rrtolt.Seals nrolt ottcc annualll ttsuallv dtrring spring or eallv sultr-

rncr' (Backhouse ancl Hervc-r 1957, Schefler l!)58, (larrick et al.

1962, Schefler ancl .fohnson l9til], Ling 1965). Thc tnte seals

(Phociclae) rcnew thcir \\'holc pelaue ir1 cach nrolt (Ling l0t3'1). Inthe casc <rf ttortheru elcphant sc:rls (,'Vlrounga angu^stirostris),

sotrthcln elephant seals (,t1. Ieonirut), atrcl Harvaiian nrottk seals

(X'IotruchtLs sthuuin.sktruli), this proccss is hastcned bl' the hairs

bcing shccl along rvith larqe shccts ol ctx'niflecl cpicletnristhrough rvhich thc club hails penclrate (Ling l9(rr-r, 1970). North-errr fur seals (Otaliiclire: (iil.lorhintu ur.sirttts) tcpl;.ttc :t1'r1llr,xi-

rrrately 7.'r% of the euard hairs ancl2ir% ancl llll% of the rrnderfitr'hairs eirch ),ear in lnatufc tnales irnrl tettralcs resPectivelv (Sdlcf'fr,'r and .fohnson l9(r3).

Ling ( l!)70) suggcstccl thitt bc-cilttse ()thcr alr)pllil)iotts s1;ct'ies

srrclr as tlrc tnttskt'al, beavct' ((kilor canadunis), irncl tivcr otter(l,utru ratuulenriri) also ttttclct'tro ottc- tnolt PuI vcar, aclalltatiott ttr

thc aqrratic habitat is uct'otnpattittcl ltv a rcdttcecl trtttrlbet <tl

nrolts.'l'his rrul lre a tcsttlt of tlrc rccltttctl sc:isottal vat'iirtion in(crnl)eraturc atrcl lesscuecl abnrsive \velll' oll the pt-lage ilt u'aler

lLirrg 1970). 1 he sc-a <>tter'(l:rlrytlra ftrlri.i) unclergt)cs :rrr cxtcllsi\cmolt clrtt'ittg sprinu. bttt thet-e is sollle eviclctrce ot ;L t-otttitlttottsturnover ol-the pelagc (Lirrg l1)lt'1). Hou'cvcr, sittglc annrr:rl nioltsrrre nol rtniclue to:r<luirtic species. A r':rrietv oi'tcrrestri:rl fttrbeirr-crs, irrcludine the recl firx, 'tvolvct'iue (Gttlo gtilo), stripecl skunk(t\lephiti.s mephitis), sp()ttccl skurrk (Spllogzrle finorhts), badger (7ax-

idea taxus),liutrrpe:rn baclger (llele.s nules), black bcar ({.'irus (onert'

rnnrr.r), pcrlzrr b ear (L'. nuLritintt.s), irncl brol'n bear ({,r. arrlos), h:rve a

single:rnnual nrolt (Ilassctt ancl Llovelhrr l9'1u. Verts l{)67, Btrr-txvs l{)68. Ling 1970, I-ong l97ir, F.stes 11180, Rue I{)81, Cr-aishcacl

ancl NIitr:hell l9lJ2, \\ilson l1)82, Long ancl Killinglcv l98l],Nlaurcl et al. ll)ll(i, Kolcnosky M87). I he ri'ilcl horses of Asia atrcl

!.trrrrpe urlso have orilv one rrtolt per vear (Line l!)70).'l'hesc spe'

t:ics hil'c a single tnolt tlnt bcqins cltrrinq earlr. spring ancl plo-t'cccls qracltralll' thtrrtrgh the sutrttner. 'fhe rr'iuter c():rl lrrows

rhrling an llrrtumn ql ()wth phasc, t'csttltittq in a fullr' llrime pelt bv

Iirlc Novertrber ealll' I)ecerrrbc-t'.(lurtrary to Ling (1970), the alctic fox has tl'o attttttal urolts

((ihcserrrort-- l{)70, 1975, Lltttleln'oocl ancl Rel'nolds l{)80). 'fhc

llrst occrtt's trrrrrr Nlarch to juh arrtl lhc secottcl llctrteett Scptetlt-ber antl ()ct<lbcr (Chesettiot-e l!)70) l)urirrg thc ittlttlrlln nrolt thcbellr,portiorr turns lltilc fit'st, ptrruressirtg clorsltlll ancl cattclirlh'.

As rvitfr thc errctic lugotrorplts, the back artcl tail 2ire tlle last t()

tunr rvltitc (Chescrriore I970).A spring lrttcl atttttttrtt tnolt is also tt'pical of the rcrl sqtrin'cl

('lhmia.sci.unu htuLsoniltti) (Pe terson l {)(i6), t accoorl clog (,\rfaallcrproc,-ornide.s) (Korltonen et lrl. l!)8'1), ltnd of sottic fitrbe:ttitrgcar-rrirrrrcs suclt as the clotrtcstic fbrlct (r\ftrslela putoritLs). short-tailcclrlcasel (,lltrslzla erntinea), lrlallclt ()lurtes anteriutna), fisfrer' (t\Ittrtes

penrunii). ancl nrittk (l.ing l!)70, Nlatrrerl ct al. l9tlli). lhe clcnse

l'inter pclage ol thc mirrk bcgitrs to shecl befirrc- the rtet' sp:rrse

sunlnlcr pela{e ctrterues, ancl :r ttcrr' rvintet c<lirt is :rlrriut hall'sr-orvn befirre thc auturlin tnolt (llutssett lrrrd l.lcrvellr. n I ()'1{)).

PELAGE,PRIMENESS['hc use of'tlifl'erent ])llrattletcrs to cletlnc "pritnettcss" has lccl t<r

a rrurnber'ot valiue (lcliritiolls, s()lll(t of llrich trlakc sctrse otth ttrfirr-qr-atlels. Iior exurrtplc, LJrtcltrzit'h (lt) 16) clefirrctl lllitnetttss rts

the corrclilion of thc fur-at tltc t'oltlest rttrcl clriesl tilrlc of tltc vcar.

l)r'irrrcncss has bc-crt ttsctl to detirrc both the lirl ancl lcltthct'siclesot thc pelt. Hcnce, clc'pcuclitrg ott the etrtcl ttse o1'thc purchtct,

plinrertcss coulcl rcf'cr to eitltc-r or both of thesel llclt sttrf:tctls. As a

lesult of rvork pcltirrrrrcrl ll'Lirrdc ( l{)Oi}:59), pt'itller tcss rvas reclc'

tlncrl as ot'crtt-rittu lhetr "lltc firr hlrs t'cachetl ils tttltxttlttttttlength, clerrsilr'ancl lltrcst textttrcl l'ltctr thc hairs have trtatttt'ccl

rr'ith seerrritrgh tto Pitlurettt bcine pnrclttcecl, ltttcl es ll cotrse'(llellce, thc tleslr strrtrtce of lhc pelt ltpl)ears tlcroitl ol lt:lit'rootyrigrrrctrl:it iotr."

(lharactcristics of l'rime Winter Pclage

Plinre l'inter firr is attlrirtccl rvhetr thc qrtal-tl lt:lirs alttl trnclerfur'have just t'cuchetl the teloqctr Phltsc-- of thc-- hair oclc. llreirrcreasccl clensitr' of the rrrink's rtintcr' pelagc is prirlralih' tltcresult ol'2i {.Jreatcl' tttttttltcr of clelivccl lirlliclcs (Rotrgcot et itll9ti1a,b). espccialh oi thc unclellin'(Allrrin ancl Rotr{ret)t 1080).

!irl cxarrrplc, the tttttnbet- ol clclivecl ftrllicles itl lhe stttntner

pclage of rnink is approxinratelv l2-1'1 per lirllicle. rilttlt'cas tltcrvinlcr firr itttains l7-20 pcl tirlliclc (Rortgcot et al. l013'14,0).

'l'tre skin atrcl thc leatltet sitle of ltlirlre pclts shortlcl:ipllearcreanrv llritc lDolnick l{)51)a, Steins 1070). lhe ct't--attn l'hitecokrr occrrts n he n thc hair firlliclc-s ettter I cloqe I r, trtc-latr iI t f ol'trla'tion in thc hair lrtrlbs stops, attd the tlcnclrites ol thc trtelatrocvtes

are 'rvitlttlt'awtr. Atrrrphv ol' the ltullrs atrcl cttttlractiott of rvltirt

r-euririns of thc filllitle--s ttpu'artl t() the lcvcl of thc sellace<ttts

ulancls (llblinq ancl .|ohusott l-()6'1) corttrilltlte t() thc chat:tctt--ris'

tic colot'of tlte leitther of rt prirne pelt (l)olrrick l1)5()l;).

liven though nurst ot the hail lcnqth is att:tittccl clttrittg lttr:r-qerr, srrch ful is not vet itt pt'ittrc corrtlitiotr. I'irllit lt:s of sltch

pclts are still sittratecl clccp in thc clc-tttris attcl, lith active

rnclirn()c\,tus, cattse tlte lclthct'antl skin to uPPeal dark ((ltrnrrl()i)2). Such pclts are lc-f'clrctl to as "bltte pelts" (Stains 1979). Ifthel arc retnoveci ltntl sauclecl ot'shavecl to tccltt<e theil-thick-ncss lurcl leight, nran\'ol thc cleepet-ltalit'roots llill bc cut ofI,causirrg rrlrt:h ot the huir to firll out. Such abrltsivc pt'ocechttcts

u'ill esueciallv atlect the rttrclet'titt-bccerttse tltc t'oots ttlunprinre unclcrhairs rtre tixttrcl cleeper in the skirl thalt tlrose

of Erarcl hairs (Stiiins l1)79). Rlclcr' (11)77) rneasur-eti thc pro'oortions of actir,c :rncl iuirctive follit:les in skin sections fionlied clccr (Oer-uus ehphus) aucl touncl that the pcak of ftrllicularinacti"'it) (tcloeen) occurrecl cluringl .fanttzrrv firr the plitnarl'ftrllicles artrcl clttt-itrg Fcbrttarv firr thc sccontiarv firllicles. Simi-larl.,; g;rrxvth of'(he under-firr o1'nriuk l'as firttncl to lag behinclgrlrvth of elalcl hairs bv appt-oxitnateh 2 ric-t--ks (Fig. 5). Rvclet'

arrrl Lincolrt (l07ti) tirurrtl thar( in Soav shcep tltc- st--t'ouclarv

(rvool) folliclcs bccatrte inaclive tttttch l:rter thart clicl tfre pli'mar-v follir:les rvhen atritnals l'ere ttraintaitrecl otr :r short pltrlto'period. 'l'hese tintlinqs asree u'i{h the obsct'r':rtiou that gualclhair tirllicles cloclop first, firllorvecl l:ttc--t lx rtnclellirt' firllicles(Dolnick I1)rr()[ \\rake I07{}).

'fhis variation rtrav pat-tly bc cxplainecl ll rlifl'elertces irr tlre:

clcqlee ol vast:ularily bcllcen tllese tw() tl'pes ol {irllicles.I)uru'arcl ancl Rucllrll (l'l)irll) slrtxtt--cl that the bloorl strpplr. to thelalecl guarcl hair-tt'pe tirlliclcs is tnttch tttot t-- cxtettsive tltlttl thatto the slnallcl trnclertirrtr'1.rc tirllicles. In lroth the rat and rabllit,onlv thc-- lalqel'firlliclc--s hnve lr vasc:ttlalizecl papilla. In the t'at thelargcl qlarcl hair'-n pe tirllicles hzn e a rich ttctrrrrt'k of capilltrrit--ssrn'rrrurrding thcil krrver hllf', rvhereus the-- stnaller tirlliclcs have

onh,a ti-'rv ttriurtte vesscls t ttttt'sittp; thtrrtruh their-supllot titrq con'nective tissue. Restirrg lirllicles th?rt l)()sscss a riclr bl<locl supplvrcc()lnnlen(:e $rrrvlh earlier than firllicles n'ith a lirniteti bloodsupplr: F-irrthcrnrore, those firlliclers rvith ltapillatt t:it'cttlatiottusuirlll'cxhibit lottqt-r qrou'tlt ptrtio<ls thatt tlrost-- ir'ithor.rt it. II'strch difTererrccs itr circttlati<)n ()((Llr itt Irtittk, thct'ivoulcl parllvexplain ivhv grorth of the urtclct'fur laqs beltitrcl that of Eralclhairs. Iiurther-rrrolc, if uncletJirr firllicles entcr (he teloeett phasernrr<h later tlrlur guarcl lrait lirllicles, this cotrlcl greath'1tfic(lt the

83-1 Wilcl l'urtrearer M:rnagcme nt and (krnservation in North America o The Pelt and thc F-ur Inclustry

trE

Fz910ElL^zaU

6

Fig. 5. Fur growth rate of young standard dark female mink. Guard hairs (-)and underfur (-.-) of mink implanted with melatonin on 20 July 1983;guard hairs (- - -) and underfur (- o- ) of untreated controls ( J. Adair, N.

Wehr, J. E. Oldfield, unpubl. data).

linre that the tirl corrrers into prirnc. F.x:rrnininq the clevelopmentot the urrrlerfirl firlliclc in clctail rnav rnake it possible to rleter-rrrirrc nrolc prt--cisch *'hen pelage l'ill be irr optinrrrrrr plinrt'< onclition.

I)rirrrerress is rrot lhc <xrlr.' clctclnrin:url of :r fur's value. Firr-

cxarnple, becrtrse rrrelittroqcrtt'sis encl the ttenstet-rlf melattin tothe hair shuli ccziscs cltrring c2rt:rge n, Peak cok)l'is ofierr attairteclrhrring :ln2r{rcn, rshich occurs sfrortlv befirre prirrtc ctirtdition is

rcachccl ttrrinq telogen. It is possible in sorne circurnst:rnt:cs firt'srrch sliqhth unpr-inre pclts t() corrirnund hiehcr priccs thanplinre pelts (Stairrs 1971)). Itrl bcgins to losc nmch of its lusterthr-ough nlrtrrr':rl l:rclinq of piqlncnts ancl becomes subject t() (lalI)'aqc fi'orlr sunlight if the arrirrral is n()t c:lrght zrncl thc peltlemovecl soorr :rfic-'r' thc lin' bccotttcs plirne. 'fhis especiallvapplics t<i rnink firl that turls oft:color l'ithin a firv u'ccks ofbccorninq plinre (()bbar-cl l!)87). -fhe tips of'thc srrarcl hair-s ofsolne species begirr to crrll, r'csulting in a "sinsecl" pelage (Stair)sl1)79)l this is conrrnon in rnink anrl river otter pelts (()bbartll!)li7). Arrirrrals rnuv ailso clirrnaqe their ol n firr thxlrglt a r,arictlof'chovirrg ancl mbbins nctions. A "nrbbetl" pclt is onc that haslalge patches ot tur rrrissirrq. olicn florn lhc shoulclers. flanks, orhips (Harnilton ancl Oook 19.16).

THE ROLE OF VARTOUS ENDOCRINE GLANDSIN THE GROWTH AND PRTMING OF PELAGENrrnrerous holnroncs h:n'c bccn shou'n to influence hair gnxvth.llorvevcr'. tlrt-- silc ancl nrechanism of actiorr of the irrtlividual lur.r)l()ncs arcr cliflictrlt to cleterrrrirre. It is uossiblc th:r( h<irrrxlrcsinllrrcnce the initiatiorr arrd rltrr':rlion ,,t urr.rserr. tlre chrt:rtiort oftcloqen. tlle ratc of'hait' $r,rr'th, Ihc t-lte ot l, ris , rf t lttb hait's, anclthe natlue of thc hail fibcr'(l-bling and.lohnson l1)6.1, !-blingl!)73. F.bling ancl Hale l1)Bli). !'urtherrntx'e, eirch of these pnrc-cssc-s rnilv be afl'ectecl ll orre ot sc--r'er':rl hornrone. lrcting inc( )llcert.

Pituitary Glandltfl'ects th:it rnost holmorres exert orr h:rir growtlt cvclcs tn:rv bernccliatecl bv the prituitalv qlurrrl :rnd lhc- (ropic honrrones (i.e.,

holrlones that act on ir spc'cific elancl) it sccrctes. lJecause thepituiturt glancl rcqrlatcs nllnle rous other enclocrine glur)(ls llrdis sulrjcct to both positive ancl nesirtivc feetlback siqnals fir)lnthcse qlancls, its precise rrrlc in lc$rl:rtine hair firllicle actiiitv isnot knol-n. Furthertrrole, fin grrlr'(h c"t'lcs of nranl species iucphotoperiocticlrllv controllccl antl the influence that tlre yritrritlrrl

gllnrl crclts on hlir grorvth rvill van' thougltout thc 1'car, anirnpoltant fiicl to rernember l hen irrtelpleting clala fi'om experi-ments inrrrlving hvp()phYsecrtorrrizecl atritnals (i.c., those l,ith thepitu itarl glarrcl lerrrovccl).

l'.arlv irlc--stigirtions on thc cffects of hvpophvsectom,v on ltairq-nxvth rvcle inc<lrrsistent. Some rese:rrchers oltscn,cd increasedqlnth rate, tlrereirs ottrc'r's obscn'ccl a decrease (\'Iohn l95B).Houssav et al. (1965) reported that hvpophl'sectomizecl rats andrnice initiaterl irnnrediatc hzrir qror,vth but thzrt the nornral rvave oflcqllvth rvas clismptecl, r-esultinp; in a cliffuse t,vpe of rcplacc-rncnl. No|nral qror'r,th \r,aves r'r'ere resurncd during thc ncxt gener-

ation of hair gll)\\,th.H,vpoph,vrcctonry of othcr species prrrduces a varietv oi'

efk-'cts. NIink or short.tailed rveasels, hypophvsectonrized rvhilccither in their suntmer olrlitrter firr, rnolted ancl regrew pel:rgetvpical ol the \\,-inter tvpe (Rust l9ti5, Rust et al. 1965). Renervedplirnirrl fbllicular aclivitv began irnmediatel,v in rnink h,vpophv-scr:tornizccl rvhile in their surnmer pelage. Il,vp<lphyscclomy ofnrink u'hile in the rvinter pelaee rcsulted in renewed ftrllicularactivitr,' approxinratelv 3 rveeks carlicr than in controls. Alierqnrrvth of the rvintcr'pclagc rvas cornplete the anim:rls began tcr

nroll irs,vnchronoush'zincl to regr(xv hair ol the rvintcr ty'pc con'tinuoush'thKrushout the )'ear. Dubv ;rnd Trar,is (1072) suggesteclthat perhaps l inter pelase is the clonrinant type ()f fur gr-orvth inrnink ancl that gro\vth of surnnrcr fur rerlrrires a special incluctil'erncchanisrn for its cleveloprnent :rncl rnaintenance. If tnrc, thisr:ould cxplain how animirls like nrink grow t$'o clistinct tvpes ofpelaee each vear In other rvords, rvintcr-type pelage grons spon-t:rneoushi l hereas gorvth of surnrnerfur recluires specific stimu-l:lt(r-y fllct()r's. In the rnink :rnd short-tirilecl rveasel tlre qrittritarv is

rcquirecl firr both the rnairttetrancc olnorrnal gr'owth c1'cles ancltirr-r'cqulatinq the grrxvth of the appropriate typc of pclaee (rr'in-tel- or surnrner).

l.lftects ot exogen()us pituitary honnones on the hair growthcvclc hilu'c also been inconsistent. In the rat, e5rowth horrnonecuuscs c()n\,ersion of infirntile pelaue to thc aclult type inlrr'Pophysectornizecl aninrals but excrts no effect on the hairs-r'o\\'th clcle (llohn 1958). Adrcnocorticotropin (AOTH) gener-allr, inhibits hair grorr th, prirnarilv bv retartlins firllicular actir,it)'arrcl emption tif ncrv hairs, but once firllicles bccorne active they!t1)w at ir normal rate (trlohn I95t3, Ebling ancl Hale 1983).

Aclrrrirristration ol A(l-I'H to volcs (Xlirrotus agrenis) cluring latesurr)r)ler significantlv dclays the onset of the autumn molt (Al-Khatceb irncl Johnson l97lD). Because exogenous ACI'I H has n<r

cffect on either spont:rneous or induced hair grolvth in aclrenal-cctornized rats, its efT'ects irppcar to be nrediated primarilythroush thc adrcnal cortex (Mohn l!)58). Rust et al. (1965) rlertr'()nstl-ated lhat injections of preenant n)are serllnl gonadotKrpin,f<rllicle-stirnulatins horrnonc (F SH), lutcinizing hormone (l.H), orovirre gonadotropin into intact mink pnrduced no obsen'ablecf-fcct on fur grorvth. Achninistrntiorr of purified FSH,l.H, thvroid'stirnulating horrnone (TSH), or hydrocortisone to hyp()ph)'secto-mized shorttailecl u'cascls also had no effect on initiation ot hairqrorvth or colrlr. Horvevef, trezrtment of hvpophysectornized $'ca-

sels rvi(h melanocvte-stimulating ltorrnone (NISH) or AC'fltresultecl in regrol'th of piunrcnlecl hairs that $'ere characteristicof srrrnrricr pclirec. Although not knorvn fbr certaitr, it appcalsthat hypophl'se:rl hormones tlo not clircctlv affcct the hail firllicle(L.bling ancl Hale 1970. 19t33).

Recerrtly eviclencc has suggested that pnrlactin may pliry :rn

irnporlant role in re6;ulating the fur grorvth of species that cxhibitscason:rl changes in pelaee (Duncan and Goldrnan 1984n).

Ilecimse secrction of prolactin appears to be controllecl by thefunctional activilt,of the pincal glzrncl, fi,rlther clisscrussion of thispitrritarr'horrnonc is presented in the next section.

Pincal Gland and Photoperiodic Control of Fur Growth\Ianv spccies cxhibit se:rsortal pelagc changcs, erc$'ing a thickclensc firr cluling auturln arrd a slcck, less clense c()at, \\,hich ma,v

also clifler in cokrr'(Rust 1965), during spring. Ilecause onset ofnrolting and rencrvcd hail grrrvth occur l,ith such regularitt', it'rvus thought tha( season:rl changes in photopeliocl nright stirnu-

//

.1-'-'

/I

2916233071421SEP OCT

11

Pelage Pr-irning o l|'ortltt t'l ul. 835

latc phvsiol()€iical chartgcs that rsould aff'ect hail snnr'th cvclcs.

Bissonnette 1itt35) rvas the first to dcnx)nstrille that light plat'etl a

phvsiological role itr ft.rr grorvlh cl'clcs of tlrc f'erret. Bcgirrning ittmicl-|anuart; ferrets rvere cxposccl to :rrt :rclclitiotral ll hottrs ollight per clal'cluritrg the tirst week,4 hortrs per dir,v clurirre the sct:'

oncl r,veek, zrncl so firrth until thev ncrc receiving alr aclclitional 6

hours of lipJht per-dal: Suppllctnertla.l lightilrg rvas c<)lrf irnrccl tlntiltlle ferrets nere tnatecl ol r-rntil 7 Julr'. Animals cxlloscd to such

lighting molted their rvintet {ul bv I April,.iust priot to p:tr tr.tri-

tion. An aclditional trvo fcn'cts ltlinclecl on I Januarv (bl scverirte

the opticr trcrve) irtrd trtaitrtaittecl on tlte above Iight sdrcclule clicl

no1 m()lt thc $'intcr firr until 21 Jull'ancl 20 Augtrst. -fhcse fltrd-

ines suggest that liglrt actillg thl()ugh the evcs is ltc'ccssarl lot-

moltirrg ancl grorvtlt of sutrtrtrct'fur lo occrtr at the Pr<)Pel tilne.

Hou,c.rer, Rust ancl Shackclftrrd (19(i9) cibscn'ecl that firr grxvthcycles atrcl gonadal activit-ies of fcrnale fclrets l;linclerl in Octobcrclicl not clifl'cr fi'om those olitrtact {'crrets, rvith both gnxrprs nrolt-

ing the winter fur clurins N{arch and Aplil ol the lirllorving lcat.Although no clct.ailecl lneasulclllents of firr Errl'th'tlcle trtade,

thev reportecl that blincling of tnales resulted in irn incotttplctcm()lt and EIo\sth ol rviuter litr clut irlg the foll<xving ,vear.

'Ihese

finrlings suggest thc presence of ctrdogerlous rhllhrns lor reprrr-

cluction ancl fbr grrilvth, rvhich rnav be svnchurttizccl ot'entt'zriltecl

lhroush photoPeriodi(r stinruli.Rissonncl.te artd Wilson (1939) rver-e thc first t() denlonslrate

that the nrink's firr grollth clcle c<lulcl bc alterecl ll1'ch;rneinu thc

anrount ol lisltt to'lvltich the animals lvere exposed. R1'gracltralll

decreasing thc arn()Lrn( of lieht fiorn l:5 NIal'thrrruuh l2 Septcrn'

beq animals of both sexes tnolted irncl gre'tl prirne u'inter pclage

bv early Scptember, rvhercas pelirge of cctntrols u'as not lll'iuleuntil latc Octobcr-earl,v Novetnber. Adair and Stout (1971) rvet't--

unirblc to repcart the effccts of ;r glacluarl rechrction in liqht otr rvitt'ter firr devclopmenl in nrink, but reclucecl lighting tv:ts rtot iuiti-ated clurins their studies until 20 .full r'hich tnav have becn totr

late. H()wcvcl, thcy rvere able to detrtotrsl.r'ate that bv cxposilremink to an :rbmpt arrcl cclntirtucius reduct.ion in claylength (tlcat'rncnts rvcle recluctiolls of 0, l, ti, or 9 hotrl's/da1) it rvas possiblc t<r

incluce carlv u'inter filr'gtxvth, rvitlt altaitrtncnt ol prillre pclage

uu to 2 months earlicr than in contt'ols (Stout arrcl Actair l969,

Siout et al. 1969). 'l'his rvas subsccluerttl!' cotrflrtrlecl bl others(Dub,v ancl'li:,n'is 1972, \4reiss et al. 1980, Rose ct al. 198'1).

Iri an elegant experimcnt,'liavis ancl Pilbeanr (l{)80) exposed

rnink to a cornpletch'revct'secl annual clal'lerleth cvt le. Aflcr a 6'

month pcliod of aclaptation thc rnink becatttc entrairlcd t() the

ncrv lisllt cycle ancl lbr lhe rtext 2.5 ycals their fur $'orvth cvcles

rvere cotnpletcl,v re.versecl. These nrink harl fully pritne l'inlerpelaec in .Juh' ancl had a firlll' dcvelopcd surnrner pelage irri)ccembcr; 6 ntonths ollt of Phasc rvitll coutrols. Analogoirs lincl'irrus ltavc bertr rnaclc bl reversing thc zrnnual photopcriotl of reci

cleir'(Krt und Rvclcr l97tl) and fcrrets (Ilan'ev ancl Nlaclrar-lanc

1958). 'fhcse d:rta clelnonstratc that thc clecrcasittg dirl'lerrgth

afier thc sumnrcl' solslice (21-22 .fun) stinlul2ites nroltittg atlclg-r'()wth of winter-fur; rvhereas the itlcreasing claylength atict'thevern:rl equinox (21-22 I,Iar) induccs molting ancl glrxr,tlt of sunt-

nrer fur. Studies on such utrrelatecl specic's as tlte rveasel (Xlunel.rL

spp.) (Bissonnettc and Bailel' l9'1'1), racc()orl (Proqort lolor) (Ris'

s()nnette arrtl (lsech l{)37), snorvshoc harc (ltlrus arnerrlanus)

(Lyrnarr 1043, Severaicl 1945), D.iunearian hattister (Phodoptts stot.'

r"oru"r) (Hofthrann 1973, l97tt), and white-fi)o{cd ntottsc ('1'zroltl's-

cus laulptu) (Lyndr 1973) have coulirtrtccl that clt:rrtscs irt

plx topeiiod zrre involvcd in rcgrrlatine seasotr:rl llair qron'tlt

cvcles.()ur kn<xvlcdge ol-horv seasonal chzinges in photope riod rcu-

ulate ful srorvth cyclcs is linritecl. Ilorvever, thc eflbcts ol photolle-riocl on hair grou'th cycles :rre probablv rnecliatecl bv the pincalglarrd.'l he pineal (cpiphysis) develops irs a rnecliatr evagirtartiotr ofthe rrrof of the cliencephalolt clurirls ctrlbr\rittic clevcloptltcnt(Hacllev l9B'1).In most tnatntttals the pitreal is tiriettte'cl irrvav lirrtrlthe third ven(.ricle but reltraius at(acrhed 1() the l)r2lin b1 a thirtstalk. 'fhe paretrchynral cclls (pinealocYles) of the pincal alcdcrived frorn thc epenclytnal lining ol'thc ellithalanrus.

'fhc pineal glan<l s,vnthesizcs a vat'ietr' of inclolt:lrtrlittcs rttrtlpolypcptides, all of rvhicfi poterrtialll cotrlcl fittrctiott as ltot'

nrones (Rcitet I9U0). Hori'crcr, it is the iuclolc:rtnitrc trlclatottitrthat has t'cceivecl the g;reate st attention.

-f hclc is rtoiv little tloubtthat urclatottirt is incleecl a pineal hortllottc, atlcl ttlcla(ouitt c:ott'

centlzr(iorrs at'c zr clit'ec( ltleastll'c of pincal actirilr'. ltt all vct'te-

br:rtc speciers cxzrtrtirtccl tllts lar the c()nccntrati<ltl of tttclatouiltin the pincal. plastna, cetcbrospittirl fluid (t;Sr), attcl trt itre is clc'vatetl duling thc clark pot'tiotr ol-the ciailv liqht/dalk ocle (l{citer1980. (lardinali I98l, (ioltlrnatr aucl I)arrrorv l9tl3, Bittrrran l9ttl).'I hc explanation ttx' (his pltcttotttettott is that light inhibits thc-

activitl, of svmpathetic llctll'ons itrtretllttittq the llirlcal firrnrsupeliot't etlical ganglia. lt is tlre rclease ol trorepiticllhriltc firrtltthese trcurotts lhat activales beta aclretrctgic recciltors otr the

pirrcalocvte sut'fitce, lcadilrg to a cANII'-trlecliittccl irr<ltrctiou ot

N-irr:ct1'ltlansferasc, the ratc-lirnitirrg cl)z)'nle Iirl' the sr rrlhesis ol'

rnelatotriu (Golclrnan ancl l)ar-r-ou l9llli).XIelat(nrin is highlv lipicl'solulrlc ancl clillirses rapirllv into tltc

qencral circulzrtiott as rvell irs itrto the OSt'(\'Vur-trnarl l9ll0). S(ucl'

ies lvith rnonkel's injectcd rlitlt 'II-ntel.tkrttirl llrtrc irrclicertect thatthe inckrlcanrinc lapicllr' ('l'()sses itr(o the (lSF ancl ecpililrrates ttrabout 40% ol- pl:rsura concentrrlli()ns (Rcppert et al' l97l)).'fhccliflelcnce betrvcen (lSF ancl plastrta is thouriht to bc cltte to pt'o'

teirr lrinding, becartsc 60-70(y'r, of tltc trlelatotrin itt plastna is

bouncl to albuttrin u'hetcas ttotte is bouttd to Pr()tcill in (lsl(Oarclinali l98l ). t{clatottirt is tuetabolizetl prirnarill ttr

6'lrt'clnrxt,melatotrirt itt the Iivcr; tghich clcars 92-l)1-% ot thc cir'culaf ing; lronnone otr ir sittglc pass ((lat'clinali l98l ).

'lhe {lrst expcrimerrtal cvidetrcc (hal tl)c pineal glancl andmelatolrin aflectccl hail. grrrrvth il'irs olltaitrccl lll llottssal et :rl.

(19(r(r). Nlale nrit:e ((i3HIF-p stlain) l)ilrealcttottrizccl zit appt'oxi'rnatclY ll nrotrlhs of agc cxhibitccl sigrr ilicantlv tirstcl hair $rxvthn':r,cs than dicl shiurt'opet'lrtccl corltrols. lilrtllcrtrlore, daily ili jec-

ti()ns ()f melatoniu itrto cight shani'operatccl or pirlcalectottrizcclnrice redu<:ecl thc t'ate of the grorvth ri'aves llclol' tltat of sharlr'

operatcd cotttt ctls. Ho$'c'"'et, becattse labot'itlot't' trticc aucl rats cl<r

uo1 possess scasonullv leprulatccl fur $rxtth cvclcs, the rolc o1'

rnclal.onirt otr hait gr'otvth in these spccies is ttot knorvtt.Rust and N4e1'cr (1969), using shot't'tailecl rveasels, rvcre tltc

lilsl to clctnonstl'ate tllat ttrel:rtottitr plaved ar r'ole in the r-egnrla'

tion ol'scasortrl fur gnrn'lh c1'clcs. NIale rvc--ascls itt btorvtt stlllllllcl'pelage inrplantetl ivith tttelii(onitt (10 lrlg itt zr bees'tlax clisk) at

iveekh, inten als fil' 3 l'eeks moltccl anci g;reu u'hite l' irttct' pelagc'

r.vhereas t'onttols leceivitrg be€ts\{2lx ittrplzrtrts t-etairrctl the Lrtrru tt

sunul)cl pelagc. \Veascls irt ri'hitc willtel Pclagie erposerl 1() artifi-cialll incleasccl clavlcngtir tttolteci atrd qlew Lrt'<trvn srttlrttrer tttt:

flon'ever; aniurals irnplatrtcd rvitlt rticl:rtottitt trloltecl atrd grel' ;r

l'hite rvintcr coat cven tlrouqh exposecl to inct'eased atrlottttts of'

light. -fhis surtic pltettotlell()ll \\'2ls obset'r'ccl in thc white-{i)()tecl

rrroirse (l.l'ttch ancl !.pstein l()76, He'ath ancl Lttrch l98l). Hofl'mann (l97ii) obsenccl th2rl tre2itlrlellt tti Djtrnuariltrt hartrlstets

*,ith nrelalonin u'hile itt rvintet' pclage clelirvctl dercloptrlettl otslurllnct fur. It has also bcen tlctnonstt irtc--cl that rrrink irlrplantcclrvith rnelatotrin (10 rnu in a Silastic [Dorv (ihcrnical. \{icllancl.

Nlich.] capsule) chrring late .Jttne-earlv Julv niolt attd trrru'r'itt-ter pelagc tnttclt carlier thitn ttot-tttal (Allain ancl Rotrgcot l9fl0,Rose et al. l9B'1).

-I'hus it appear-s th:rt exoqc--nous ttte'lertottitt tttitn'ics ttrc efli:ct of shor'l d:r1's itr iuritnnls erllosecl to lotrg pllrotoperi-ocls. 'fhc abovc fintlinqs sllggcst tlt:rl l'eclucecl davlight'itrdtrceclrnolling antl gr'ow'th of willtcl pelagc is metliatccl itt pat t thrortulttlrc Ditte;tl lt,rt lr)r,tlc tttcl;tlottilt.

Seasonal cltatrges itt s-vslettric prolactirl coltc:c-trtt'atiotts lirrrnarl species have bt--ctt sltorvtr to bc photollc-rioclicalh corr'

trollccl (Iluttle l!)74, Bex et al. l{)78, Pc(et-s atrcl'lirckcr 1078). Ittnrink tlrc spritt{ ancl rttrltlltltt utolts :rt'e con'clatecl uith iltctcars'

inq ancl cleclcasing ltlastuit-prolactill c()llcelltlations lcspec'tiveh (Allain et al. l()ul, Nlirltinet ct al. l-()8lrz,D, l1)ti3, Rose et al.

19811).

Ilestrlts ot t't--t:cnI tcscarclt sttqqesl that pltotollet-iocl-r'c'latecl

clrangcs irr plrlactin scct-etiott are tcgttl:rtecl, al ltlast itt l)art. l)\'

rrrclatorritt. Nlartinct et al. (198i3) clctnottstl':rtect th21t ct()lrrcslic

rnink cxposecl 1() a reducc(l claill llhotopcriocl ol girctl itr jtcti' 'ttsof rrrclalorritt pt'ior to the sprine ntolt hacl significarltlv t'cclttced

plasnur-pt'olzictill c()nctetltl'il.tions; thcir spritrg trlolt u'as t'ctal-tlccl

iirr as lolrg as plastna-prrtlaclin ctxrcctrtl'ati()Ils t'etlr:ritlecl lttu'.

lJ3(i \{ilcl F urbearer Management ancl (lonscrvation in North America o The I'elt ancl the }ur Lrdustrl

F-ultherrrrore, pnrlactin injcctions given 7 tlavs afier nlatinginclucc-rl sprinq nrolt in nrink at an eariier date than norlral (N{irr-

tilrct ct al. l{)t3lll). Achninistration of nrelatrlrtill t() l)lalc l)astclnrink (Allain et al. l9ttl) :rrrcl st:mdarcl dark rnink (Rosc et al.l0tl5) fiorrr l:tte Aplil to carlv Julv causcd a prclnatLlre lecluctionin plasrria-prrrlactin concentrations; Ixxvever, ir'r contrast t() thcefl'ccts of melatonin on thc sprin{ rnoll (N{:rrlinct ct al. ll)lt3),nroltirrg arrcl reqrrru'1h o1-thc u'in(cr firl l'clc cnhancecl. NIaltinclet al. (108,1) subscrluentlv clemonstrated that nrirrk nr:rintirincclon a long photoperiocl :ttter- the sunlnler solsticc cxhibitccl a

<lelal'ecl recltrction irr plasrrra-pr'olactin conccn(ra(ions anclrnoltecl ancl regr-err' firr th:rt, basccl on lirllicirlar clcnsitt'ancl clilec'tiorr ol thc gr'oulh wavc, \{:ls ch:rrircte ristic of the sumrner-t1pe. Irrc()nlr2ist. appr'oximatell'half the nrink rrrairttairtetl on a kxrg plro-toperiocl ar)(l tlc?rtcd rvilh llrrrnocrl'pl.ine (a ckrpaminelgicagorrist) exlribitc-'cl ir siqnillcantll' callicl leduction in plasrrta-prrrl:r<:tin ('(xxrcnlrati()ns ancl nroltecl ancl grerv ri'itttet' pela€c irtan earlier time. Hol'ever, nrink rnlrintairtecl ott a sh(t't plx)topc-riocl ancl treate(l u'ith prrrlactin still rnoltcci :rncl qr-cw nirrter'pelaue.'fhe" spcculatccl th:rt thc bovinc prolactin (bPRl-) achnin-isteled to thc nrink stirnrrlalccl an inclezise in encLrgenous prolac-tin c()nccntrations that upset the errtir-e hornronal brrlance of the:urimals. lt is unfirrturrlrte tllat rnink niiiintaincd undcr natrrralphotoperiodic changes n'ere not treatercl rvith lrtrrrttocr r ptinc.

Kerrtauav et al. (l9tt2) have also clelnonstr2rtcd ir rclatiorrshipbet'rvccrr thc' pituitur'l arrcl pineal glancls of ther shccp. \Vhcnshccp u'crc pinc-'alcctotttizetl, pl:rsnra c()ncentrations of' rncla-lonin rvc'r'r'rcclirccrl to or berlou the lirrrits of cletection in thcir'ass:r1: Oorrt'ornitantlti horvclcr, thc nrcirn 2,1-hour pr-olactin levelsapproxinratelr, cloLrblccl. F.xoqcnorrs nrcllrtorrirr irr Silasticirnplartts tcdtrced plirsrrra c()ncentr2rl.i()ns of plrlactin irrpincalc< t<xnizccl shccp us xcll as slr:urr-pinealectortrizccl shccp.()f particulal intcrcsl in thcil sturh n,as the obserr,ation thatex()!ren()Lls nrelatonin clicl no( altcr thc cilcadiarr rlrlthur of nrela-torrirr sect etion, irrclir:ating that there is no ncgativc ltcdback ol'rrrclittonirr on its ou'rr svlrtllesis (n-secreti<ln.

Prol:r<'tin l)lay stilnulate firr grrru'th of mink cluring the springnrolt, as shou'n lx,N.Ialtinct ct al. (11)tt3), arrcl rrrar,inhibit thealltlllnrl nrolt until horrnone concentr2r(ions dcclinc to Lrasal ler'-cls. R<isc ct al. (1987) slro'rved that adrlinistration of bronrocr'\'p-tinc 1o rnink lirr' 3l-r clay's dulirrs surrrmer- (25 .fun-130 .ful)enhancecl rnolting of the srrrnrncr pclagc ancl lapicl growth ()f

rvinter-tvpe firr. Because bnrrnocll'ptinc s(rl)prcsscs prrrllrctinsccrcti()n, Rose e1 al.'s clata inclirectlv supPort the hypothesis thatthis qon:rckrlropin rnav inhil)it $rxvth ot lr'inter pelage in rnink.Adclitionallr', Dun<':rn :rncl (lolclrnan (l913.1li) shorvecl thalI)jtrnuariarr harnsters that were gir,en clailv injcctions cil ovineprolactin (ol'Rl.) n,hilc irr rvirrter pelage, ancl rvhich rvcle sultsc-(luelrtlv pluckecl, urerv back pigmentecl hail chalactclistic of sunr'rtrcr iiu: ;\lterlativel'"; hunrstcrs given in-jeetions of prrrlar:tinrvhile rnaintaincd on 2i sll(11 l)lx)t()pcriotl ltacl irrlribitecl moltingancl gr-on'th of rvinter-tr,pc firr' (l)uncirn ancl (iolchrrarr 19{3,1a).'llrese tinclinss rrgree rvith those of Rrrst (l{)Or5), rvho dcrr)on-stratc-cl that sholt-tailccl l'easels lvith pituitall' autotlansplantsunclcr thc kiclncv capsrrlc rne\{ pel:rqe charncteristic of the sunr-nrer t\,pe even r.vhen exposccl to cnvironrncntal stirrmli thatinclucecl gr<rrvth of l'intcr firl in inl:rcl anirn:rls. It is possiblc, u'ithtro ltt'Pothalarrric inhibition of prolactin synlhcsis ancl serclction,thut thc \\'cascls'errrkrgerrous pnrlaclin leve ls increasccl ancl u,clcrcsponsiblc firl nr:rint:rining thc rvcirscl in its sunrnrer- pelage.Horiever-, Rougeot et al. (ll)8,1a) :rclrninistcrcd Ptrlirctirr to rninkrxt a short plrotopcriocl (ttl : l(iD)ancl fuilecl to inhibit thc Iall nroltzurcl qrollh ol'uintcl lirr: Unfor-turrateh, (letails r-egarclinq lhcquantin of pnrlac'lin adrninislclccl n'c-rc not giverr urrcl no experi-lnents \\.erc t onrlrrt'lc<l x'ith rnink cxposed 1o natuliil changcs ilrplrotoper-iocl.

Adrenal filandsIn gcrrclal, holrnoncs of thc arh'cn:rl glancls cxcrt an inhibit<x'refTbct on hail erorvth (Nlohn l1)ir8, l-blins ancl Hale l{)tt3). \{inkaclrenalectolrizecl thrrirrg sprinu rlolt and grrrrv sunrrner pelagerrruch ca.rlicr thirn in1:rr'1 anirnals do (Rust et al. l9(i11). Stutlies

rvith rats (Nlolrn l95B) :urcl nricc (Davis l96ii) havc clcnrorrstratetlthat alter atlt'enalectomy onlv the initialion of hair gr'eu'1h is

accclcr?Itcd; the tirne requirecl to produr:c cach h?rir isunchanqccl. It appcals that products of the acL'enal glancls cxcll :r

c()nstallt restr:lint ()n thc initiation of arragerr ltut have no eflectiifiel hair'$rrn'th has been initiatccl. ApProxirnatcll irO sternricls

halc bccn oblaincrl Ilorn tlre cor-tical c()llDol)ellt of the rnarnrna-lian :rch'cn:rl glancls (-lirrrrer- urrd Basrlu-a ill7ti). llecarrsc aclrcnal'ect()lny u'oulcl lcrnovc all thcsc horrnones fiorn the circulation,simple replacement theral)\'ivilh onc (r'lw() c()11ical horuronesrvoulcl no1 crorrrpletelr,clefine the r'ole of (hc aclrcnzrl glands in lrair$ ()\\'th.

F-erv irclrenal honnoncs havc bccn invcstigatcd l ith regartl tothe ir eflects on hair snlrvth. NI ink given dailv subcu t uncou s in jt.c-

tions ol l.0 ol 1.5 rng hr,clrocoltisone u'hile irr rvinter- pelage f aileclto molt ancl gr-ol'slllnnler firr (even afier pluckine) trntil injci:-tions rvere discol)tilrued (Rust et al. 1965). (loltisone or A(ll I I hasbccn shorvn lo rcducc rvool eno'rvth and tlle cliarneter of 'rr,ool

fibers in sheep (Linclncr and Fcrguson 19116, l'erg'uson et al.1965). l'hus, ex()qen()us cortic()stcr{)ids appeilr to affect nrorethanjust initiation ofrvool grol,th in shccp ancl havc an overalldepress:rnt eftect. l'urtherrnore, rvhen aclren:rlectonrizcd cucsu'crc givcn itrcrcasing closes of cortisone :lcetate, l'ool grrlttthclecreasecl prrrgressir,eh' irs thc closc of cortisonc u'as incleiisercl(!'erguson et al. 1965). ln contrast to olhcr'<:ortit:ostcroicls, clcoxr''col'tic()stct oids appeiu to be rvithout anv eflbct on hiril g'orvth inthosc spct ics cxzirninccl thus f zl (NIohn l9:'rlt).

'I'hc sitc of :rr:lion of sonrc adrcnal horrnones on hair snxvtlrmav be clirectlv ()n the hail folli<:lc.'ltrpical zrpplication of cirltit ulhormones has been sh()wn to inhibit firlliculal activill'onll inthosc arcas that \\'(--r(-- trcatcd (Rakel et al. I9,1lJ, \{hitaker anclBaket' l{).18, l!)i>1). \{ltiteler, (l9l-r{3) clerrronstratecl that aclnrinis-tration of cortis(xrc lo <:hinr:hilla raltltits hatl ir rrrole uronounccclinhibitorr, eflbcl on unclerfirr fibcls than on grr:rrcl hails. It u'us

poslulntcd that cortisorre irrhibitecl regn)\rth bl' interfeling rvithrcvasculalizzrtion of Iirlliclcs alld that. bec:ruse the vasculatur-e ofunclcrfirl folliclcs is rnuch lcss lhirn that ot' suard hairs, Ihefilrrner l as rnore :rfI'ected

'fhe lole of aclrenal meclulla horrnones in legulatine hair'qrrrl'1h is far lcss unclcrstoorl tharr that ol cortical lrormones. Ratsrecciving nr.icc'daily injcctions of 0.1 rnq cpincphline extribiteclrather-prorrouncecl initial delal's in hair grrrrvth aftcr' pluckinu,bul orrce it begarr hail gro'rvth ri'as normal (Ilohn 1958). f,pineph'rinc rnarkccllv inhibits sponllurc()us l'eplacernent of hair. 'l hervave of folliculal activitl spreircls rnuch rnorc sloivll,atrcl the siteol injection is "b1passecl." \\'hen hails eventuall\, qlxr, in thisarc:r thcv alc unpi{rnt--nted.

'fhyroid G,landIt is rvcll cstablished that the tlrvrrrid glancl plal's a nrajol role inreg;ulating the hair gn)wth c\,cle of nulllell)us species (Ebling1973, liblirr g ar)d I Iale l9tt3). Oharrg ( 1926) first obserlecl that tht-roidcctonlr'inhibitccl hair $or\th in r?rts, iur cflcct that has sinccbccn confirrncd bl' othcrs (Dickc 19,113, Bakcr' 1l)irl, Zccku't--r'19113). Aclministratiorr of tll lricl hor-rl()nes t() intact animals usu-:rlll enhances hair-grou,th. lr-eetment of r-uts rourplcting tl)eir'lirst leplacerner)t wave ol hair grrluth n'ith tlltrxinc prrrrnotcclearlicr'lrrllicular aclivin (as dctcrlrinccl br thc cnlpti()n of nc\\'l-rairs) ancl a lnore lapicl passage of the grrrrvth l'ave (L,blinq an<lIohrrsorr l9(i.,1).

Inhibition of thvrrricl elancl activitY ivith rarrious q(,itt)q( r)ic

agcnfs such as prrrpvlthioulacil (PlLl) generallt, r'c(ards hair'replacenrent (\krhn 195t3). Irr rats that receivecl a solution of0.02% Pl Lr instcad of ch'inkine \ralc-r, rcncwccl f<rlliculal activitvirr the heacl rcqion of both scxe s \\'2rs clclayccl fin' approxirnatclv1(X) clar.'s (l-bling ancl .fohnson 196.1). \\Ihen rrrles rver-e qiren u

s<rlrrti<rn of 0.02cL I'lLI ir)stead of rlrinking n,ater'. rnoltins atrclqr'o\\'th of the spring pclags 1vg1g complc(clv inhibitccl (Al'Khateeb ancl lohnson l!)7lD).

()rre of the tirst clues to rvhich aspect ()f tlle hair sxxvth cl'cle is

inflrrc-nccd b1, thc thlr'oicl qlancl n'as proviclccl bv Fleucl (l-91il),rvho obsen'ecl that hair gron'th irritiatecl br, pluckirrg was n()t

l'elage Prinring r llorlln',.l al. 837

inhibitecl in thvroideclotnizecl rats. Sitlilar lcstrlts rvet c t cportetlbt' I,Ioh n ( I1)ir8), rvho trcated r'rtts ivith I'l L; irtrcl fi lt r rcl th:rt. exce plfin' an initial clelar, hair gr-ol th rtncl tpal it1 of pelagc u'cle ttoI tttztl

in elcr'1'respect zrftct'hail trrlvt.h'tvas initiatecl b.' llltrckinu. Sporl'tar)c-()us hair grrltvtlt, horvcvet, las rctitrcle<l Iix't.he errtitc clura-

tion ol thc stucll: -fherefirre, il appeals that a thltri<l'<leficicntstatc- inhibits onh initiation ltncl earlv s(ages ol ltair gultltlr. ()rlcehail Eorvth has s(artecl, rvhcther- sp()lr(ane()tls <x' itrclttt:ccl lllplu<:king, tlte tl'rlroicl glirncl exerts littlc or Ito cf-f'ect orr follit:trlar'irctivit,v (\Iohn I95r8, F.bling ancl Johtrsott 1{Xi'l). 'f}rc thtr-oicl

elancl tnal' be partlv lesportsiblc lirr terrtlinatiolr o{'thc telogctiphaseofthehait cvcle.

Scveral irtvcstig;ators have obscnt--tl a relatiotlsllip bclrvccrtol:rsrra levcls of thvrrixitre atrtl atrnual nrolt cvcles. Irr thc harbot'ieti (.Phoca uitul.ina), prlastrra-tltrtr,ritrc lercls trct-e firuttcl t<r

increasc significarrtlv irs tlte attitnirls ttroltccl attcl gt'crv theit suttr'

rncr pclage (Rivicle et ul. l{)77). I}oissin'Agassc ct al. (l9tll) clcrn-

onstlatecl the existent:c of a biphasic sttltsotlal rltt i:ttit'tt ittplasrna-thvroxine lcvcls ol aclult tnale trrittk. Highest thvnrxirrcconcerttratiotts t)ccttn'ecl chtring sprinu ancl autllrllll lrlolts artcl

lorvest concentr?Itions clut itrg tr,intel-. Nct crtheless, thc role of thcthvroicl g;lancl in leerrlating trtolt cvclcs of tnirtk is < ottttrrvt-t'sial.Rcineke ct al. (l9ti2) chenricalll "lhvroitlcctotnizetl" rnink bradnrinistering large ckrses ttfl"rl rr'ltilc the attitlrals rvert itr lheirsulrlnler pelagc. Althouch lhese lrtitrk cxpet iclit ecl a rrotrtrlll filllmolt arrd gr{)\rth ol *itrtcr pelagc. t.his'tvas latcr attl il)itlccl t() t}l(lpresencc of thl'roidlike sulrstttnces irl thc rliet. Aficr t orllplctiorlo1 $'inter fur elon th tlter rrtink tqere Pllrcccl olt ir sc-rn illtrriticrl clict

fiec of me:it products (to clirttirrlrtc all tlrtrrrirlal sttbstartccs) atttlsubsequcnllv fliled to molt attcl {ll'()\{ stlll)lllcl- pelaec. Fttrtlter''rnolc, in anothcl grortp of'"(hvt-oiclcc(otrtizecl" nlink tllal \\'('rcfecl a clict contaitring a sYnthctic thvtr)ln'()tcin, plrltial t() c()lllpl('teregrowtll ()f lhc su ttttttcr firr <tcctttTelcl, inclicatine the i| | I I tt )l Irl Ilccof the th,vroicl gJlancl in leg;rrlatirrg lhe fitl grol'th o'clcs ol thesc

:rnirrrals. Hou'evc-t, Rust e1 al. (10611) cotrcluclecl tlrill lhe tllrrriclglancl hacl no cff'ect on thc firr $rrxlh cycle ol'tnink. lrr llrt'irstuclt; neithcr surgical thy'roiclectottrv ttor aclttlinistrati()ll ()f'1ll\'-

roicl porvclcr had irtrv obsetvablc cfI'ect olr lhc sllrirru ttroll atrtlp;rou'(h of sutttttrcr firr. Unlirrturtatelr, itr neithct ol'the :tlroltlstudicsdidtheirlc-s(igatorssltavcthetrtirtkancitakcttttlttlal tltc':i'

srlrclncllts of firr growth, rvhi<:h $<[r]rl halc pRrviclccl 2t lll()l c prc'cise inclication of 'tvhcn firlliculal at:tivin rl'as iliitiatecl.

If thc th1'roitl glancl plays tt trrle itt terrlrinatilrg thc tekrgenph:rsc of the hair c1'cle in nrink, this ittfirt-ttrtttiotr lllav Palllvexplain thc l:ru prior to tht- initilrtion of hair-Erru th itr trtel:tl<ttlirl'trcatecl rnink. Rosc ct al. (l9tt'1) obscnecl thirl tnittk trelrtcd \{itl)rnelatonin duling late .func clicl n()t exhil)it t'ettelcrl hliir qr<xlth

until ll 4 \\'ccks l:rtef. I1 ttrat'bc that hair ql<rl'th tloes rrot treqittclut-ittq this peritlcl ltccause thvroi<l ltolttt<ttttl c()ll((llll-itti(rll\h:rve rrot vct riserr 1o t:t'itical levcls. lt tttlt\ als<t be that thc'tllroitl:rncl pineal qlancl hortturtrcs act s)ltcl'gisticalh to t't'uttlate ltltit'qnnr,th.

C'onadal HormoncsIt is reasortirblc to ctxrclttclc tltat qonaclal lt<tttttones itrllttcrtcehair-grou'lh becattsc gnxvth t-atcs atrcl ph1'sical <'har-lrctc't'istics o{'

hail rliff'cr betrvecn nrales artcl I'cnrales. Firt'cxanrplc..jtn'cllile litt'ol'r':rts is sirnilirr betri'eett thc sexes cltrring the lirst livo gtrrirlhrvaves. Ilorvcver, by thc thircl gnrrl'th cyt:le tltc hair of tttalcs is

much coalser than that of fernalcs (NIohn l()5t3), a biolouical clrat'actcristic that cxtettds trt ttr:rles of otltct'species as rvcll (NIorrtltQtra

ancl I'arakk:rl 197'1). .fohnsorr (l958rz,D) obscnctl that in lcrnalealbino rats h:rir gr-ol'tlt rvat'cs Itrttvc'cl tn<lt'e slon'lt'ovcr thel lloclr.the dcfinitive lenelh ()f the llrit's $'as sltot tcr, ancl Ihe loss of clttlrhairs rvas slower than in nralcs. In seasottallr bt'cetlirrg rtl:rtritnals,ch:rnges in pclaee ()ccul'('()llcollritantly'rvillt cltalltltr itl reptr''cluctivc conclition. Itr the cltxtrcstic fer-rer1 (Harlev arrcl \Iac'l'arlane 19513) antl Djtrnrrariarr ltiurister (llol{inann 1978).

alteratiort of photoperiocl, rvhiclr ittflttttttt es gotlatlal tlevclop'rnent, also aff'e t'ts hair' $rxvth. ln thc I'crret attcl ttrink, cle c t cirsitrgclavlerrgth intluces reytrorluctive tltticst ettse, rnoltirlq, itltcl qrrtu'th

of n'inlcr' pelagc, u'het-eas itrct'casittg rlar'lcugtlr stillrtllates

incleasetl gottaclal activitr: rtroltitrq, atrtl $rr* th of stttrltltt t fitr.I)rrlinq l)r-eqllanc\ zrtrtl l:rt'lation tlte sp()r)t?urcotts replacc-

nrcnt ()f hair is rroticeabll t'cl:u'rle<l itt rats atttl rnicc (\lohrt l!)ir8,Nknlaqna arrcl I'arukkal l()7'1). ln tlte ervc, plcgtratro is ass()ciatcdivith a rechrccrl clc-:rtr llcece rveieht artcl t ertc- ol'ivool grori'tlr, n'lticltcorrtirruc's thrrlrqh the sr.rckling pcliocl (Re icl l!)78), itlthotrqh thecllccts ()f l)re!t-nancv alc grcittcr thatt tltose ol l:iclali<ltt. ltt cott'tlast, hiril e'rrrl (h x'ave s in rrr ice ce asc drrrinr: late pt-eett:tttct ;rtrcl

ckr rrot |csunrc until atter strcklinq encls, eitltet at $catritrg or olttlre plcrlrirlure r-errrovul of xxrtrq (Iiraset-atrcl Nur l()lirlJ, Nav arrdI'l ascl l!)55).

r\lthouell lriglr svstcrnic ( oncerltlali()rls ol proeestet<)rlc ltlct'hanrcter-istic ol plcltnancv itt ttuttttttrirls, lhis hot-tttottc ill)pcarsto havc no cf1bct on hiril slrrl'th itr thc lat (Nlolrn l1)1111), rnouse(Davis l96ll). or sltc-cp (Slcn ancl (lorrrrell l1)58). Hrxlever. Flttrrorlet al. (19(ili) clcnronstr-aled thirt:rcltDitristt'ati()It ()f pr()g(--stct'()ltc lo

I)rc-rlnant rabbits rc-drtt'ccl the h:ril loosctritrq atrcl sheclclirtg trtn'rrr:rllr ,,lr.t nt rl lrr irrt lo 1r;rt lur ili,nt.

Slorver puiss:rec of the grxltlt rrzttc ancl the lirrer'hairs chat'ac'teristic o{'fcrnalcs have bcc-tr shorvtr to be duc plinralill to theplescr)cc of esttrrgens. Firt' cxatnple, in fi:rrralc zilbino t'ats tltethilrl gcner-atiorr o{ Iirlliculllr activit\' (i.c., thc secottcl postrratirllcplacerrrerrt ol lrrr') lreeirrs ()n tllc \c-ntr2rl sur-iace .tt .tltpti'xi'nratelr'(rll clavs ol aqe. spreitcls to thc tlot'sal strrfacc lx lX) clavs, altclis corrrplc'tc'bv a little orel lirO clals (.f ohnsorr l1)li8D). H<xvever, irr|ats that rvcre ovaric-clortrizctl at'19 claYs, Iirllictrlar-activitv l)cganon the verrtr-rtl srrt'l:tt c at aboul tltc slttric- titrtc as itttact atlittilrls lxttspread to thc clolsal sttrtitce bl 66 clavs, rvith firr elrivth beingcorrrplc--tc lrt onlr'!)2 tl:ns (.fohnson I1)580). Also, clttb hairs l'ere'Iosl nrore r':rpicllrl u'ith neu lrait grrltth being- siurrillcatrtlt lotrger'in ovulicclonrizerl rats. -['hc loneer ]ltit-s lrc-tc atlril)tlte(l to a

fastcl qr'(xrth nrte all(l r)()l to a lottget clttt'lttiotr <lf altagelt.In rats ovut'iectotnizeil a1'1!) clars ltrrl itnplarttetl \{ith cslre(liol

(5 nru I0 %, csl r:r(li( )l in cholcstcrr rl), firllicu lar- activi( v rv:rs tlelavecluntil :lPproxiuratelr'llir clat's ancl clicl rrO( sltt't'ticl to tlte clor.s:tl srrl"

fnt'e lrrrtil Il0 clavs (.fohrrsorr ll)58ll). In rats tllllt u'ct't-- txariecto'rnizetl attcl givcn claill sttbcttlatreorts irrjerctions of estr-acliol( l(X) irg cstlarliol rrrorrolrcttzoetc), folliculal activitv iu tlte rctr(t'alrcgion rvas delavecl until applr)xirrratelr' l)lJ clavs. li-eatrnctr( otovariectorrrizccl lats l-ilh estra(li()l :rlso t'esrtltetl in hait'lengthslhat were signillcantlv slurt tet th:rtr lhose of oraricclotrtizecl ani'rrltls lr-r'civinq lx) tlcatlncrrt lrr.rt nhich \\'cl'c ll()t shortet thanthosc of intact arrirtrals. Also. the tatc ol loss of clttb hirit's rvas

rcrluced bclou that of intact ferrtzilcs. Hale arrcl liblirtq (11)71-r) alstr(lenx)nstlr.tcd that ()\'al icct()ttiizctl albirto lats inrplantecl uithesllircliol hli<l rechrcetl harir grol'tlt ratcs :lncl slrorter hrtirs. lttrl.rrott'itrrp<lt'talltl\l thcv u'ctc rtltlc to rlt,ru rhtrt tlrir ltotrtl<ttrtl ltlstr

rc--clircc<l the cltrlatiotr ol anagen-utt cf li--< t trot rtstritllr':x'hiclecl.l-strrrgerr irrjc't tions have bcc'tr shon'tr to ittltiltil sltoutatreotrs

r-eplacerncnl ol'hair irr nticc ancl <krgs (Nlolrn ll)irll). .lackstxt antll..bline (l{)72) obsclr,ccl a similar eflect ()f'cstl'()serrs ort Iirr gt'ol'thr:r'cles oi thc grrinca piu (Oatia portellus). nhich hits rt ttt,rs:tit llrtt'ter-rr of h:iil r-cplacerrrcnt. ()\'arie(torrtizccl guittelr prigs tlcatecll'ith cstla<liol hacl tcchrcc<l hair $rrrlth latt's. litlr inilia(iort otanaqcn being clelavccl bv tnore tltatt 2 rvccks. It has also ltccrt tlenr-()nstrate(l that loPical application of esttttgtrttic cotrtltoultclsirrlrilrits sl)()ntane()us lcplac errtettt of hail irt r-:tts lltrl rloqs (1\Iolrn

l-()58). thus irrtlicating a Possiblc rlire<t actiott of t'sttrrs*ett oll tlrtrhair firllicle.

'[']rcsc' clala irrclicatc- that, ilr thc lcrlralc. estIl)gclls cxcrl allinhibitorv eflcct on hair grou tlr ctt lcs, slori ittg thc passage ol tlrcgr'orvth lilc. inhibitirr!r shcrlrlin{r ol cltrb ltrrit's, attcl irrrposille a

liniil orr the lcrrgth ol the lrair'{llrcl lt is 1,rossiblc that plnsioloui'callv higlr cstr'()Qcn c()nccl)lr'?rti()l)s trtitt clcl:rt lhe ()llsel of atla-qen. l]()l(linq Ihe tirlliclc in thc leloqctr phnse'of tlrc h:tit' o't'le atrtltlrrrs rcpr-eserrtirrg palt of tlrc tcgttlatort tttcchattistrt of ltaitgrou'tlt.

( ]orrlrclll hrlrnrorrcs ckr I)()l seeur t() cxcfl as pt-ofi rtttrcl an eflet t

orr nolulrl hair'$rru'th cvcles irt tnalcs as irr li'tnales. .fohnsolr(19l-rBD) <lerrrortstt'att'rl tltat trralc rats castlatc(l at 7 u'ccks or c:ts'

tlirlc(l an(l t|catccl witl) test()stct'otte sltouccl t'ene$'ccl lirllicrtlalactivity irr lhc'r'cntral lcgiotr irt abottt thc s:rttre tilttt-- as did illtaclanirrurls. Hrlu'evet-, cllsll'2iti(xt specclt'cl tll) Ihe gn()\\'II) \\'llvu ovel

83u \{'ilcl }urbearer N{anagement and ( lonsen,ation in North Arnericir The l'elt antl the Fur lnclustrv

the boclr', rcchlcinq thc tinrc to conrpletion of lhe coat bt u-10rvccks. hnplantati()n of test()stelulre irrto castraterd rrrirles slolcclpassaec of the gr'orvth n:ne to a r-ate sirrrillrl to that ol intuct rrnlcs.Definitive length ol hails il) c?rstl:rtccl nr:rlcs ancl lalc ()l l()ss ()l

clult hai|s, rvith or rvithout lcstostcr'()nc tfcalr)rcnt, rvr'r-c nol siq-nificantll,cliflelent fi-orrr those of irrtact arrirrrals. Sirrril:l lr:, \'lohn(l95rtl) reported tl)at the arn()unt of slrontancous $'()wlh intcst()stcl'()nc-t|ciltccl, ('astr';rtccl r:lts clicl not sienificantll cliflerfi'orn that in r':rts that w'ere castrate(l onltr Also, hair gr()\\'th atter-pluckine in gona.clcctorrrizcd anirn:rls trc2rtccl intliunuscularh$'ith 200 pg tcst()stcronc pr'()pi()nate in oil $'as consiclerecl Dor-rnal. r\l-Khatccb :rncl Johnson (l{)7lr) clcnronstlatccl that rvherrnr:rle v<lles were c2lstrated in auturnn. hair reulacerrrellt \\:rs ilriti-atecl sever':rl ueeks earlicr. Ftuthcrrrror-c, caitlatccl rrrlcs qlcl'acoirt thzi( rvas ch:rr':rcl.cristic of' rvinter pclaee ancl r,as nlrclrdcnscl le garclless of l hether the voles n'ere kept on slr()rt ()l- l()r)gphotoperiocls. lrr the recl (leel, castlr,rti()rr irppcarccl to ltarc ttoefl'cct ()rl nrolting arncl qrrxvth of cithcl sulnrllcr'ol rvintcl lirl irranirnals rnaintirinccl on a (i'rrronth annual clal'length cvcle (Kayancl R1'cler 1978).

CONCI-USIONSNluch knorvledgc llas becn accluilcd about thc stlucttu'c anclfirn<:tion of hair ancl cspc<:i:rlll ab()ut zrnat(nnical ancl ph1'siologi'cnl changes th:rt chnracter-ize cvclic hair renerval ancl grrlrvth irrnlost nlarr)nlals. -lhc prirrrc rvintcr'pc--l1s ol'u'ilcl attcl corrrrrrc-t'cialllgtrrrvn firrbcar-crs al'c cconornir':rlly irnport2rnt, ancl rcscar<:ir irrrcccnl Years has fircusecl on the f:lct()rs that regSrlate growth of'rvinter pelage. Iilrrn this lese:rrch, clata have enrergerl suguestingth:rt the redllcecl hours of cli.n,ligllt dul illc fall result in irrcleascclscclctiorr ol llelatorrin of'pineal gland <x'igin, u'hich in trlrn sul)-prcsscs scc|ction of prrrlaclin frrrrn Lhc pilrrilar)' glancl. r\PPar'-cndr.' it is the leduction in the systemic concentratiorrs ofprolactin thlrt perrrrits gon'tlr of winlcl plelage. I lorvever, further'rescal'ch is nccclcd 1o dctcnninc thc si(cs ancl rricchnnisrns ofacli()n of melatonin and pnrlactin in legulating the gr'ol'th ofrvintcl pclaee. Also, it is rrot knorvn nhcthcr lhcsc hormones ar-e

also involvccl in contrrrllirrg 1ri$ricntation of hair: Ciollectivell.such research nrav leacl to the devek)prnent ofcorrunelcial plocl-ucts that coulcl enable fur ranclrers to hasten grou'th of ftrllvplir nc-- r,,' i n tcr' pclaqc in varrious im i nrnl s.

l)ifI'ele nces betleen prime rvinter-pelagc ancl surrrrrrer pelagehave beerr docurrrerrtecl. Holr'ever. rro ch:rracter-istic has bccrridentificd that c2rn cersilv bc quantificd and usccl lrv the ful inclus'trl lo rne:rslrre the clegree of pelaue plinreness. Hence, lhat corr-stitLllcs prinrc pelauc contirrrres tO bc tlcte|rrrirrcrl cxclusiveh blsubjcctivc cvaluation. A rnolc' objcctivc rncthocl ol nicasrrling liu'cluality is neeclecl. Hair micx)anatomy stuclics shoulcl prrrbablr,bec()nducted irr search of phtsical inclicators of the prinre hair. lil-exarnplc, (hc cli;rnrctcl of thc cc-ntral colc o1- thc- hail shafi (thcrneclulla) varies corrsiclerablv not onll rvithin but alnr )n{ spet ics.It nray be useful to detcl nlille bv electrorr rricnrscopl, Ihe meclul-lart diarncter:rnd conrposition ol'lriiil of r':rrious aninrals duringthe prirnine pl'occss. Recausc such f rrct(r's u'ould influerrce thccokrr tone of hai4 thev rnal'be paltlv rcsponsiblc fol conrplctionof the prinring pr'ocess aftel nraxirrrurn hair length has bccn:rttaittctl. I1 is presurrtecl that a rrrore sirrrplitiecl rrrethod of irscer-taining thc' Prinrcnc-ss o1-Pclaec uoulrl cvolvc {irrrr tlrcsc initialstuclies (e.e., one that coulcl reaclily be usecl in thc flclcl ol' coln'rncn'ial trnit lx'usc ol a light rrricloscoplc). Strclr u lrlcthod base(lotr thc rttictrranatorrrl ol lrlrir coultl tlrcir be uscrl ll n ilcllite rrran-aprers IirI CStal)lishillq tl'al)pir)c s.lrs()lls und b\ tl'ul)l)c|s arrcl tirr'ranchcrs fi)r'clc(crl)rining plinrc-rrc'ss of pclauc-. ()lx iouslr, sirclr a

trrethod coultl also be usecl lx the nrar-keting segrncnt of thc firr'industrv iis al)usis lil lilrthclcrrsulirrgrrnilirlrrritr' ol pelts sokl irrlols:rncl firr revarnyrinu thc plic<'s pai<l lil pclts.

LITERATURECITEDAl)AIR,.1.,A\l)HNl.Sll)tlll l'!)7l. NIinkrt'st'uxIr: tontrolltxIlightarrrl

lirtlirtg. ()t eson Agl'ic. !.xp. Strr.. Spcc. Rcp. 320. 2tipp.Al)()RL\\..,\. S...\Nt) (;. I]. K()t.H\()sK\'. l9(i!). A rnur[r:Ll Iin the irlen.

tilication ol h:rirs ol sclcctccl ()nl;rrio nlrrnrn:tls. ()nt. \linist. \at.Resour'., Res. Rep.lX). (i-1pp.

,\t 'KH,\l !.f.R, r\.. A\l) F.. .J()l l\S()\. l97lt. Seasonal chanses 0[pelage in tlre vrlr (,1lzaalir.r.€)zf/l.r. l. ( lorrclat ion l ilh t hanqcs in thccnrlot rinc sl;rncls. (ien. Orrnp. F.nclocrirrol. l6:217 22lJ.

-.-\\l)-.

l97lr. Seasonalcharrqesof pel:rqeirr therrrle(.,\Iitrotus rigrr.rlir). III.'l'he rolc oI tlre cnrlocrinc s\ster]r. (icrr. Oonrp.l.nrkrt rirrol. l0:21](i-2-10.

Al.l..\lN. I).. L. \1.\Rll\1.. 1..\.\..l) .J. R()LI(;liIl. l1)81. I.-IIi:rt ol nrcla-Iorrin irrrplanls on t harrgcs irr lhc ( ()at. plasnrir prolat tin level :urcl testiscvcle irr tlre rnink (,\Iuslehuisort).L'aces 2()ll 271 irr R. ()rtavant,

.J. l'clle-licr, iurrl .f. Il RavaLrlt, cds. I)lrotopcrioclisrrr ancl rel)r1)ducti(rl. I\R-AI)ubl.. I)lrris. Fr:

, .ANl) .J. R()Lr(;l.l()1. 1980. Irrtluclion ol aulurrrn rlorrlt irr

nrink (r11u.rlr,1a zrl.inn l)c:rlc an<l llcaLnrris) rritlr rnel:r1onin. Rel)r)(1. Nutl:Der.20:l!)7 201.

At R!lR. 1,. l1)r'r2. t hc llr:ll(nrv ol firllicles prodrrcing rrtxrl-llbres, uitlrspecial rel'erence t() kelatirlizatiorr.'lharrs. R. Soc. Lrlirrlnrslr62:11)l 2ir.l.

ll.\(lF{R-{(lll, \1. 19.16. Fur': a ptactical tleatise. Rer. etl. }'r'entice-Ilall,Nor \trrk. N)l (i(i-lpp.

ts.\(lKIl()lrst., K. Nl., ANI) li. R. Illl\fl.lR. l9ir7. Behaviour of lhc srctseii lHalichttenLr gar/rr.r F:rlr.) in the sprinu. ['lrc. Zool. Soc. l,orrrlorr121):4in).

Il-\Kl,lR, R. L. 1951. 'l'he lelatiorrslrip oI tlre arLenal. tlnrrricl. arrtl pitui-tan ql:rnrls to tht'qrorvth o{'hair. Ann. Ncrv \in-k -.\cacl. Sci. irll:(ilX)-707.

_.D..J.I\(;r_l.],(t. Il.l.r,.\Nl)Il.NI.I..\-r\\s. l0.1tt. (irorrrliinhibi.tion in the skin inclrrtecl lrr parentelal aclrrrirristr':rtion oI arherrocolti-cotlrpin. Arrat. Rec. 102:llll] llil2.

B.{sS}ll'1. (i. F..,\\l) 1.. \1. l-1.1.\\'lll.l}N. l!l.1fl. 'I'he nroltirrs ancl lirrur1)\\1h pattern irr tlrc atlrrlt silver Iirr. Arn. NI irll. Nat. lll):ir1)7-(10 l.

-,.\NI) -.

19.19. 'l'lte trtoltiltg arttl lirr {rrrrrrth pattern irtthe arlLrlt rrink. r\nr. \l irll. \iat. -12:7rl | -7irtl.

Br.rx, li..\. R.\Rr Kr... Il. I) (;()r.r)\r.{N. A\r) S. DAr;r'r.rRr() 1978. I'lrlac-tin. grrxrlh honronc, lrrlcinizing hrn-rrrone recel)t(n-s, :urd seasonalclrarrges irr testicrrl:rr activit\ in tlre goltlerr lrarrrster: !-rrtkrcrirrokrqr103:?0(i!) 20ftO.

lllSS()\\l.l l ll., 'L lI. l93ir. Relatirnrs o[ ]rair Gcles irr lerrets trr

r:hanges in thc:rnlcrior llpophvsis anrl to light clrles. Anat. Rec.(il]:lirl) l6lJ.

.{NI) F.. I.l. ll.{ll.l.\'. 19,1.1. F,xperintental rnoclilicatiorr arrdrrrnlrrll <lf nrolls anrl clr:rngt's of toat-tol<lr in rrcascls lx <rlnlrolltrllightirrg. Ann. Nerr \irlk.\cad. Sci..lir:221 260.

-

, A\ l) A. (;. ( lSlI ll l. l1)37. \lotl il-rcat ion ol rnanr rnalian senralcvclcs. \'ll. Ftrlile nrelirrgs ol r:r((oons in I)ecenrber instencl ol l'elrnr-ar v irrrlrrcetl br irrclelrsirrg rlailr' peliorls of liulrt. Pxx. R. S<>c. l,onrkrrr.Ser: ll 122:2.10-2ir.1.

{\l) Fl. \{ll.s()\. 1939. Sh()r'tenins clarlisht perioclsbclleerr Nlar li :rrrrl Septcrnlrrr l2 arrrl thc pclt ocle ol the rrrink. St i'ence lJl):.1 |8-.1l1).

BI I INL\N, 1... t,. l1)8.1. \lclat0nin :rn(l ph()toPcfiorlic trrne llellsrlre-r]rent: e\i(lellce Iirrrtt trrtlettts all{l nlnlirrrnts. I'rrges liri l!)2 irr R. .1.

Reiter, ecl. l he pinc:rl glancl. Ruven l)rt'ss. Nerr \ir-k, N].li( )tsst\ A( ;,\ss 1.., L., I). NIAt-Rt.t.. .\\l) .1. I]( )tsst\. l1)lJ l. Scasonal Vari-

atiorrs irr th\r'orirre:rrrtl testosterone levels in relation t() the rrroult inthc arhrlt rnalt' nrink (,\Iu.stt4a lr.rori Pcalc :rnrl l3carrrrris). (ian. .l. Zool.50: l0(i2- I (Xi(i.

llt l.l.()t-(;H. \\: S..,\\l) l'-. 11. 1.,\l'Rl.N(11.. l1)58. l hc nritotir activih of'tlre[irllicle. I'j:rues lTl 187 lrr\\l\lrntasrr:rarrdR.A.].llis,ecls.'Ihebiol-ogl of huir anrrrth. Ar ark'rric l)rcss, t.vcrr Yrrrk, N)'.

Bt-RR()\\'S, R. lg(iE. \\'ild fox. 'laprlinsel l'Lrbl. (irr, Nerr Yrrk, Nll202pp.

llL. t"l Ltl, I I. 1,. I {}7.1. Season al var i:rtitlr ol prrrlact in il plasrna ol rnale

uoats. .f . Rcprr rcl. Fcltil. 1]7:1)ir-1)1).(lAltl)1x",\l-1, D. ll l!)81. \lelattnirr: a rn:urrrnaliarr pineal lxrrntne.

Hr rrk rcrine Rer. 2:1127-lt1(i(.,\RRr(.K. R., S. I_. cS()ril)As, S. l_. I\(;rr.\\r,.\Nr) K. Kr.]lrr. l1Xi2.

StLrclies on lhc sorrllrern clcphant se:rl.,\lrlrn.q'a lronlna (1,.). Ill. t hcannrr:rl crcle in lelation to :ree und sex. ( lSlR( ) \\rilcll. Res. 7: I | !)- | (i0.

(ltl\.\, K..,\Nt) .J. 1.. \lON l f.l'l H. l{)7ixr. [i-anslcr prrrccsscs in aniuralcoats. l. Rarliativc tlansfi'r. Pxrc. R. Soc. Lorrrkrn, Ser: B lUu:377 i]!)il.

.\\l)-. ll)75b. liansftrpR)(csscs in animaltr>ats.ll.( lor rtluctiort an(l c( )llvecti()r ). I't oc. R. Soc. Lotttkrtt, SeL l] ISll:il-q5-l I l.

(iH,\\(;. II. (1. 11)2(i. Spccilic inllucnce ol the tlrvrrrirl slanrl orr hairql1)\rtl).Arr..J. I'lrrsiol. 77:ir(r2 .i(i7.

(lFl,\Stl. ll. B.. ll. R.\l-(ltI,.\NI) \. \\l S\1t'lH. l{)51. (lritical staces of'Ir:ril clevekrlrrrrent :urd pitIrrrent:rti()lr in tlre rrrouse. I'hysiol. Zrxrl.2.1:l-lJ.

(illl.Rll\', R. ll.. A\l) 1,. \'LRNlllt. l1)7ir. Seasonal acclirrlrrizurirrr krtenrper':ltule irr the plairie role, ,\fiallr.r ochngnsler..\nr. NIicll. \at.1)-1:l:i5-1 l](i0.

Pelage Prinring o ll'ortlry et ul 831)

(lltl.,Sl.NI()llI, D. I-. l!)70. N()tes ()rl thtl Pel:ttle lttlrl llrilltirtu se(ltlellce

ol arctic lirxt's itt trrr-f hcrlt Alask:r. l. Ilarnnlal. irl : lir(i- 1 51).

l97ir. I'lcolosl ol tlre lr<tic l<x (.\lopa lriarlr.r) in NrrtlrArrrerita: e rerieu'. t'ages llll-l(ili irr \1. \\'l lirx. ecl. Ihe rrilcl tani<ls:

thcir svsterlllti( s, belt:rr ittral ecoloql alltl exrltttitlt. \'rtrl Nostt:tlldReinlrolcl(io.. \ew Ytrrk. NI'.

CRAr(;Hr.,\rl J. J., ,\\l) .J. .\. NIl llllll..l.l.. l1)fii2. olizzlv bear: I)ascs

ir I 5-556 rn .J. r\. Ohaprrratt :rrt<l ( l. A. Felrlhartrer, ecls. \\ i lrl r r r:rr rtttllls ttf

Nolth .\rnerica: biologr'. rtlArl;rqe lrtellt, ltlltl ecottolrlit s -lohrrsHopkins Lin ir: I'rcss. Baltiniorc, NIcl.

l).\NF()RI H, (1. Il. 1925. liail atrcl its rel:ttiotl to (luesti()lls of ltttlltol'ogt alrrl }rhr logenr: AIl. .J. Artat. ilti:'l7 (ilt.

DAVIs, ts. K. l9(i3. Quantitative Ilttnpholouical strrclics rtpolt tlre influ'enceo1'tlreenclotritre svstetrronthe grrrtthof lt:tirll *hitt'nlice..{cta!lrrclot rirrrl. (()opcnltagen). Strppl. 85: I - I 02.

DluK!1. S. H. l{).+ll. 'l'lre cf}cct rtI rettrrtvittq rariorts t'tltloctine glallrls

on the hair ctcles ofblack rats. l'.nrkrcrirlolog-r''12:l]Iir-il I1).

D()t.NI(iK,Fl.H. l1)ir{)a. I'rittrirtu'ttpof hairirrtheniink.\atl.FrtrNovs3l :20-21.

l9ir1)b. Ilistogcncsis ofhair in thc rttink:ttttl its rel:rtiotrsllilltoclennal letal I:rt tt'lls. .1. Nft r-phol. I05:I-3|

l9(il. I.Ilairsrrxrthinthernink.N:ttl.FurNovsilil:12.ll)65. A crtntparative sttttlv ttI tlte skin ol [itt belrrcrs: tlte

Iirnctiorr:rl trrlc of sttttre cotrrtcctive tissttc cltlltellts. I'ages lirir-161 zrr

A. O. Ltnc ancl ll. F. Slrort. ecls. 13iokrgv ol'thtt skirr ancl hair enrl'th.Anulrs arrtl Rt)bcrtsorr l.tcl.. Sftlrte\; Atrsl.

I)R\: l. \\i 11)26. 'lhc coat ol'thc tttottse (,lltr.r nuscultLs) .J. (ienet

l6:2|J7-l]'10.DLlu\', R. U, A\l) tt. ll I'R'\\'ls. l!)72. I)hotOPe|iOrlit tttlrtrrrl ol lttr

rrrtrrvth irtrrl rcpr<rtltttliolt irr the rrink (t\ltrstel.u uistttt). .1. l.r1l. Z<xrl.

182:217 225.DLI\( 1,\\, \1. .f ., '\N l) B. D (;( )I-l) \1AN. l1)U'1a. H< r-tnotral t esrtl:rt iotr ol

tIre attnual pelaee color cvcle irr thc l)jurtgariirn hltttlstetl 1% ttktptts surt'grrru.r. II. Role of l)I1)l:rctin. .J.I'.xp. Zrxrl.2l)0:1)7 l0ll.

l9u'1r. llortttottal r(tqatlati()ll ol tlte arttlLtal

lrrla{e tolttr cvcle in thc Dittttg;rriett hat}tstef, Phodopus.rutlqlrtls. I

Rolc of the gon:rtls arrcl the pittritarl: .f. l.x1t. Zrxrl.2ll0:ul) 1)ir'

I)t R\\ARl). A.,.\Nl) K. NI. l{tll).\1.1.. 1958. 'fhe vastrtlari$ :rnd plttertrsof'growtlt ol'liair firllicles. I'agcs 181)-2lfl ln \\'. Nlorltasll:r attil R r\'I'.llis,erls.'fIre biokrgr'olItairetrrl'tlt.Ac:xlctttit Press,\ervYtrk'N)"

l-ut.lN(;, U .f. l9(iir. Srstetrtit Iat:tors :tll'etlins the periorlicitl o{ liairfirllicles. l'ages ril)7 52'1 irt A. (].I,r'ne antl B. F. Short, uls. Biolosl of llteskin anrl hair ertt* th. Alretts attcl lLolret tsotr 1,1d., Svclrte\l r\trst.

1973. I lrrrrtones :rlrrl ltair grrtrvth. (lostrtetit s alttl lter-littllcrlftlJ:.11 -.15.

-.-\\l)l),\.FIAI-!..

l1)70. IhttcoItttrrl ol thcIttarttttlltlilttltttott]tNIcnr. Soc. F.n<locrilrol. l8:2lir 2117.

-,

.\\l)

-

. l1)83. H6rrrx;res :rrtrl [ail grrrrvtlt. Itages ,522-

.152 irr L. A. ()oltlsltith, crl. lJkrcherrtistr-v attcl pllvsirtloel ol'thc skiIr.

\rrrl. l. ( )xfircl Llnivcrsitr'['ress, Nt'rv \irlk. N]'.

-,A\l)

t.. J()l l\S()N. l{)(j.1. I hc actiorr Ol horrnorres t)n sl)()nta-

rreorrs hair qtrrrtth ctcles in tht: rat. .f. F.rtckrcritxrl.2-9: l1)l] 201.

F.:il !lS,.J.,\. f {)1J0. linhvlra lutri.s.\llrnttr. Species \o. Iit3. 8pp.f',\R()()q.\., \'. H. l)l'.\t.Ntll'lR(;, S. ROSS. I'. l]. S.\\Vl\,.'\Nl) l\1. X. Z.\R

R()\\'. l9ti3. Nlatetn;rl ltchavirl' ill the rabbit: crltloctitre fictrlsirrrrrlvecl itt hairloosetriIrg.,\rn..f. I'llsiol. 201:27 | 2 t'1.

F t.R(;L-S( )\. K. ,\., A. 1.. ( l. \\'.\1.1..-\C!1. .\l.'l) H. R. Ll\l),\.-llR. l1)65. Hor'rrron:rl reqrrl:ttion <>l ltxrl growllt.I'ages (iirir ti77 tn r\. (i Lvne antl B. I:

Sh<r't. ecls. lliologr ol llrc skilr artcl hair errxvth. .\tlstts:tllr[ lLol)erts()ll

[.tcl.. Svclncl Aust.l.l{AS}lR, r\. S., A\l) l. N.\\'. l9r'r3. (irrrrrlh ttl tlte rtl()tlsc c():lt. II. l'lllect

ol sex :urrl preur:rtro.: Aust..[. I]iol. Sci. 6:ti'11'r-(i56.

l"RllLrl). .1. 193'1. lhq;ophlsis alttl hair Act:r lJrevia \eerl. [)hvsiol ,

I'h:rnnacol.. \l iclrbiol. '1:1)!)- 100.(;()l.l)\1.\N, B. l).. .\NI) .J. NI. I)ARR()\\: 1983. 'l'he pincal ulanrl alril

nrarnrn:tlialt photopet iorlisrrt. Nertroctrrlrtct irrokrtl i]7:ll8(i-l]{)(j.(lLrNN, (1. K. l1)32. (lolttt rtttcl ltritrteltess itr varialrle trratrrtttrtls. AItt.

Nat.66:ir.lti 551).

t l,\l)l,l'.\', NI. I'.. lgu'l. l'ltrrlt>ct ittokrqr: Pt entit t:l lall Inc., l'.trslertotxl(llillis. N.f . .;17pp.

I t,\Lll, I)..'\..,\\l) F. .1.l.Bt.lN(;. 1975. I he elletts of cpiliation attcl lror'nr()rr('s()r)the:xtiritvol'rirthair'[irlIiclcs..l.lirP.Zool l0I:11)-(i2.

H,\\lttjl()\, \\l .f ., JR , .\Nl) D. R. (l()()K. l9 l(i. Prilttetress, ctrrtlitiotratrd firrvalues. ll-arts. Nrrth'\rtt. Wilcll. (ioItl lI:Iti2 I(i7.

H,\Rl)\: Nt. H.,.\Nl) A. ( i. t,\ Nll. 195(1. l'trrl.rosctl terttritroloQt lirt urxrllirlliclcs in sheel). \atule 177:71)5 70li.

H.\Rt-()\\: H. .J. l1)8-+. 'l hc ilrlltterrtc of Il:tlclitrian gl:tncl rctlroval:ttlclfirr lipi<l rctttor':tl ttrt lreat loss:ttrtl later llttr 1o:rrtc[ firrrr tlre skitl o{'

rnrrskrats, Orirlalru zibel h ic us. Plwsiol, Zool. 57:ll'11)-ilir6.

II.\RRIs,(;.D.,H.D. IIt:PPI,A\l) -J.A.(;r.SS,\Irl,\". lllitit. 'l'hethcrrnal

corrrlrrct:rrrcc of l'irtler atr<l sttttttttttr pelaue of l'rpu-s talifintirus. .1.

'l herrrr. Iliol. I0:7!) 81.

IL\Rl, .J. S. 19.r(i. St'asonal chaltqes ilt ittsrtlation ol the [Lr: (ian. -f

Ztxrl. i]-1:.iil-57.H-\RVE\, \. 1.... ,\\l) \{. \. tr.1AcE-\Rt.,\\ta.

lertgtlr on tlte coat-slretltlittg cvt les. lrocllthc ferlet. r\ttst..l. Iliol. Sci. I l:187- l{)!1.

ll.\LrS\I,\\, L. A. l!)32. llic crxtical firsi.\rn. )iat. (i{i:1(il -170.

I1).+.1. Applietl rnicroscopr of liair. Sci. \lonthly irl):l9ir-202

II!.,\lH. H. \{...\Nl) (;. R. lttr..(lll. l9lil. lllI'ects of l8 *eeks o1 <laily

nrel:rlonirr irrjet:tion oIt re1;rotluctiotl rln(l fclrlPellltttrc rcQrtlatitttr itlthc rrxrrrse, /)r'rot nlst u.s I a u o p us..|. F.rp- Ztxrl. 2 l6: I 1)il l1)5.

H()[[Nl.\\\, K. 1973. f he itrfluclrce o1 photopcriocl lttrcl Irlelatttrlitl()n tcstis size, brtrlv rveieht, atxl Pelzrq€ col()tlr in the l)-itrnu:tt-ian harrr-

stt:r (l'lu ttlopt t.sstnur;rl.r). .1. (i<rnp. I'htsiol. liir:267-282.

l1)78. hlli:cts ol short pltotoperiotls ott pttllcrtli g;lxlth :rnrl

rrrorrlt irr thc f)-iunuariart h:ttttsler (Photlopu's stutgtrler). .J Rqlrotl. Fel'

til. r5-1:21) iJir.

H()L:SS.\\. .\. B.. (1. Fl. t'-l'PrlR,.\\l) .f . I l. I'AZ(). llXlir' Neurrth<trtlrtrtrtlregrrlation of the Irair cvclcs itt l:lts an(l tttice. I':rgc 6'11 65'1 in A. (iLvnc antl tl. Fl Slur, ecls. l he biologr' ot the skin alttl ltail gnxstlt.

,\rrllars :urd Rober tson, I -t(1.. S\(llte\,,\tst..J. I l. PAI(). .\Nl) (1. Fl. l'.PI't-R. 11166. Etlbcts of the pineal

elanrl upon thc hail o't lers in Inice. -f

. ltnest. Dertrlatttl. '17:2:]0-23'1.

.J.\(.KS()N. I)., -\Nl) !l .1. l.Bl-l\(;. l1)72. 'l he at:tivitv ol'liair firllicles and

tlreir re sp( )nse f() ()estrirrtk)l irt tlre auirlca'piu (kuit porttllus |" .f . AIrat.

lll:iJ0l] ill6..J( )l IA\Sl'l\, K. 1962. l3uo1':rno luttl insttl:rtiotr in tlte rllttskrat. .f . NIaIrr

nral. -11]:6-1 (iti.

.l()H\s()\, t'.. l1)irlla. Qrrantit:rtitc stutlies of liair cllrllth in the;tlllintrr:rt. l. \tnnal nr:rlt's altcl I'enr:rlcs. .f. F-.nckrcrirtt>1. lti:3117 :i50.

1958r. Quantitlrtive studies ()l hair grorvth itr the alllirxr latll.llrctllctt,rlrctlt,,ttttottes.-J.l.rrrl,',lirr,rl.ltl:lijl-:li1).

. 1977. Seasort:tlthalrgesittthcskittoItllatlrltrals.Srltrp Zool.

Lonrlon il9:il7lJ -10'1.

. l9lJ.1. Seasonal atlaptiver coat cll:lnllcs iIt ttrittlrm:rls. Act:t

Zrxrl. l'e nn. l7l:7 12.

.\\l) .J. H()RNBY. 1975. Seasotnl t hatrses 01' pelaue irl thtlrrrc rleer ( Qtreolus ultrnLu.s attcl its nrlc iIt therrlroreq-ttl:ltioll. J. Nat.

lIist.!):ti11) 62f].K.\\'' R. N. B., A\ l) \1. t-. RYI) llR. 197U. ( i()at gR)\!tli in re tl cleer ((,'anrrA

rlaplitt.t) cxposecl to a tlat'lelrgth cx le oI sir tlrolrtlls clur:ttioIr. .1. Ztxrl.(l-onclorr) lE5:ir05 irI0.

Kr..\ \A\\r{\,, l) .J.. 1. A. (;ll-\I( )RI.l, ,\\ l) R. Fl Sr..\ \11\RK. I9u2. llllects 0f'

rnclalonirt inrplaltts otr thc t ircacli:rtt rhl llrllt ol'lllasIIta ttrel:rtolritt :utcl

prrrl:x tin in sheep. l'llrtlttcritrolosv I l0:2l8tj-2l8U.Kt.L:(;Fr. A. O., ll. l-. ITRYE, K. .l()llA\s!l\. K. F. Llr.Nt, (1. R. NOR,\(iK. I. l).

()LS!.N, .\Nl) A. J. \\Al t.R\1,\\. ll\ t- t'. (ilx)rrliite stmctufe :rIXl

lirnctiort. 2trrl t<I. \lacni illalr I'trbl. (1o., Nel' \'rrrk. N.L ti2tlpp.

K()l-ll\()sK\', (]. ll. 11)87. I'olar bcar: /n NI. Norak' .f. A. Baker, \1. !-.Obbarrl, arrcl Il. NIalloch. e<ls. \\ iltl litt|eercr tttartltgctnetlt lltrd coltsel'r :rtion irr \orth Arnet it :r. ( )Ittario li-appers Asstx., Nrxrh llat:

K()1.1.-\R. I'1. .J. l1)70. l he ittrlttttiotr o['hair firllitles l;t etnlrrtrtltic tlcr'rnal papillae. .f. lrn'est. Dernratol.55::17'1 :]711.

K()Rrr()\!r\, I1.. NI. H.\RRI, .\Nl) .1. AS[K.\lNr.N. l9ti'1. \loultins and

se:rsonalpel:reevariatiottsitrtlreraccootrrlog.Actal'hcriol.2t):77 88.

KRYlil Z( )\l r\. l. 191i1. Nk[rl t tolrourapltr o[' NI icrotittae, othcr rodellts:Lncl lau<lrrr r'phs. Z. Satrgctit'rk. 29: I - I 7.

Ll\l)1.-, A. H l0(;3. Nltrskrat Pelt Patterlls :rtrtl plilnctress. \'\'isconsitr( knsen: I)cp.,'lbch. llull. 29. {i'1pp.

LINI)\l.R, t l. R.,.\Nl) K. A. Irl.R(;t:S()N. 195(]. Irt[lLtcucc <>[ the arlrtlr:tl( ol tex ( )rr rvttttl qtr ru'l h atrtl its rel:ttiott ttt "ltrtak" attcl "tentlerttess ' ttf

the 1k'e ce. Natrtt-c 177:188- lltl).LI\(;, .1. K. llXlir. Hair elol'th lrntl ttrrttltitrg in the sottthcrlr elephant

seal, rllirottri.qn leonina (l.irtrt). I'ages 52ir ir-1-1 rn '\' (1. Lvne alld B. ISlxr t. e<ls. [Jioloqt of the skitt ltrrl ltait qrrxrth. AltgLts lrtltl Robertsolrl.trl.. Stclrrel, r\ust.

l1)70. ['elauc antl ttroltiltg itt rrilrl tnatttnt:rls rvith special rcf]

er( n(cl,r:Iltt.rtir lorttrs.QR<r.l]i,,1. l.i:l{i ]l1972. ,\rl:rptive fitlrctirrrs ()1 \'ertebr2rtc ttrtltitlg cvclcs. Anl

'ltxtl. l2:77 ll3.198 1. F-pitlernrrrl cvcles lrrttl tttottltitlg iIr III:tlitre trlatttllt:tls.

\rtu/.,,r,1. li rrrr. l7l:.llt i.lti.

l,( )N(;, ( l. .,\. l1)75. \lolt in the Nr rth Atttet ican bacl get','liuililu taxus. .1.

Nlanrni:rl. ir(i:!)2 I -l)2-1..\Nl) (1. r\. Kll.l.l:i(;1.!l\'. lt)83. |he barlsers oI the rvorld.

( lhalles (1. I lxrnas I)trbl. ( io.. Sprilrgtielcl, Ill.'10'lpp.I-\'\1A\, (1. ll l9'+3. (l()rttrol ()l co:tt trrlor itt tlle Ianirtg liare, -f-rllr

anrerrrnrttt.r l'lrxleberr. lltrll. \ltrs. Oornp. Zool. 1)li:301) -161

LYN(lll, (;. R. 1973. I'-lIect ol silrlrltllttcotls cxP()stlrc to clillbrerlccs irlplrotoperio<l alttl tetnpcratrtt tt ttlt tlte seltsrtrlal tttolt alrcl rcptrclLtt tive

195u. 'I'he ell'ct:ts ol tlavwciglrt, lrtrcl rt'prttclttctiotr ttI

of rrrarnnralian lritir shalts.

)()t

8 10 Wild Furbearer Nlzrnagcnrcnt an<l (lonsen'ation in North Americir o The Pelt ancl thc Fur Indusn

svslt,rrr ol tlle \\lrite-li)()te(l rrrousr. Ptrony'.st tt.s l.etuolttts. (i<lntp. Bklcheru. l'htsiol. J.l.\: l:J7ll- Il'i7(i.

A\l) A. l-. [.]'St l-t\. l1)7{1. Nlel:rtonirr irrrhrccrl thanscs inuorrarls, pclagc :rncl therrrrrgerric cltarattcrs in the ulrite-lixrtetlrrtouse,l)rram)srus ltulltu.s.(,om p. llioclrerrr. l'ltvsiol. irii(i:(i7-68.

l) \1., r\. (i. l-()(;{i. 'l'he clerek4rrntrrt of hair lirllicles. ALrst .1. Sci.28:1170 1177.

\1,\R|r\r. l. I_., l). ,\1.1..\r\, .-\\t) \1. NIt,]'\rr.tR. |l)83. Resularion irr

l)reglant rrrirrk (rllaslala zrl.ron) ol plasrrr:l l)rr)geslrlr)lt('atrrl ltrrrlat tin(r)n( rnt r:rt i( ) ns lurrl |egultLtior I Ol orrsel of 1 hc s1 l|i ng rrl rult ltY rlar I iglttt:Ltio arrtl rnelatonin injections. Oan. .f. lxrl.6l:11)irl) l1){)3.

.\\l) (i. \l'l..lNl.lR. l1)lJ+. Rolc o1'ptrlactirr in llrt'plrotol;erio<lic conlrol of rnorrltirrg irr tlte rrrink (.,\Itt.skla tisori1. .1.[..nrkx rinol. | 0l]:!]- I ir.

-.(i..{l-1.-\lS,ANl)

l)..,\1.1..\lN. ll)lJla. l he roleol prolattin an<ll.l I in lutt':rl lrrnctiorr arrcl l;lastoctst grorvtlr irr rnitrk (,l1l.i1r1rr ll.vrr). .f.Rcprorl. ftrtil. Suppl. 2l): I |1)- I30.

\1. \ll.I \llll{, .\\l) I). ALL.\l\. ll}fJlr. (irntrol of rlcllrt'clirrrplarrtation ancl orrset o{ spr-inu- rrrorrlt irr tlre trrirrk (,\lrr \ltl!r t,iult)1ty<l:rvlight rati(), pl()laclilt:rnrl nrellLtonirr. Paur:s 2irlJ-2(il ll R. ()rtavanr,

.1. Pcllcticr-. arrd.f. l'. Rltvault, crls. I)ltotopeliorlisnr atrrl leprrrclrrctiorr.INR.\ I)Lrbl.. l'aris. l.\'.

NL\Ul{rr-, l).. (i. (l()L r.\Nl. t.. l}()lssrNA(;ASsl.t. .\Nt) .J. B()rsst\.198(i. Scasorlrl rrrorrltirrq l)altcrns in three Iur lrearing nlurlrr:r]s:llre l.rrrope:ur b:rlscr (,Ilelli lrrlll L.), thc rtrl firx (lirfzrr lrrftn 1..):rrxlthe rnink (,i1r.i1r,1rr lriol). A nrorplrrikxrical rncl histol(xii( rl stucl\. (latr.

.J. Zool. (i t: l7ir7 l7()-1.

l\l()llN, NI. ll 1958. '[']re t'lIccts ol rlille|errt Ixlrrxrn:rl st:ltes on tllegrrrrrlh ol lr:rir irr rats. l)lucs 335-31)8 il \\i \lont;rgnlr:rrrtl R. A. I,-llis,etls.'l'lre lriokrul ol hltir errrl tlr. ,\r'luk'rtric l)ress, Nerr \ork, \)'.

i\l()\'l-r\(i\.\, \\':, A\l) I'. I.l P\R.\KK.\I.. 197+. 'I'he Pilu|r app:uarus.

l'aqes l72 25uin lhcstluctureantllirnrtiortol skirr.iJnlt'rl.-\r:rrlcrnicI)ress, Nerv Ytl k. \}'.

-..\r'-l)1....J.\:\NS(i()l'1.

I1)irfl. ilrearr:rtourr ol tlrchaillirllicle.I)eqcs lJ-() (i-1 rl \\'. \ftrnt:rr.1n.r.rrr,lR. ,\. l..llis. t,ls. I hc ltioloet of heirqrrxvtlr. Acarlt'rrric l)ress, Nerr' \'ork, N)'.

NI()t \ l. l-. 1979. Atlal;lation to tlrerrrral cntirrrnrrrerrt: rrr:trr arr<l lris

1;rrrcluctivc arrinrals. LInir: l'ark Prcss, llrrllirrrtre, Nltl. il3 | p1t.N,\\'. 1.,,\Nl) A. S. IrR-\Sl.-R. l1)55. ()Rr$th of tltc nrorrse co:rt. \l l_[Ircts

ol prt'un;tnct arrrl l:tct:rlion..\rrst..f. lliol. Sci. li:.1?ll -1ll.l.( )lJ RA R l). \1. [.. l!)1t7. F ul elarlins antl Pelt irlerrt r Iic:rtion. /z \1. Nor ak,

.f.,\. llaker, i\1. li. ()bbarrl,;urrl ll. \lalkrch, ctls. \\ ilrl lirrbe:uer nranest'rrrerrl an<l t onsclr;rtiotr irr Nortlr,\rnt'r'itir. ()rrtario lr-t1t1ters Assoc..North llai:

()l)[.-\Nl), (;. t-. ll)fJ3. Stnrcturc ol thc skirr. l'uges li (ili ln 1.. A. Oolcl.srrrith,ecl.llioclternistrlartrlphrsiologro[thcskin.\ir].1.()xl<xlt.nir:I)rcss, \er'\'<l k. N.\l

()I-l\-lllf. R. t'l l91i(i. \{ltisker srrlltlt aliel rt'nror':rl ol tlte rlerrn:rlpapilla:Lrrtl lensths ol thc firllicle irr thc Iroorlecl lat. .f. F.rnlrrrrrl. l.-rp.\ft rrphol. Iir:ltl'tI iJ.17.

l1Xi7. I lre experinrcntal irr<hrt tiorr oI l ]riskcr qrrrrr th irr tlteh<xr<le<l lat bt irnltlanletiort ol'clerrrral ltaltillec. .f. litrrlrrnrl. l.x1t.\[rx p]url. llJ:-lll-irl.

It)70. I hc inclrrction of lirllit le Iirnnlrtion in the lulultpapillae. .1. I'-rrilrnol. Fixp. Nlorplurl.

Rrll\l..KI,l,!-. 1'., 11.F. lR,\\'1S,,\\l)1.. II.D()l-.\.'l(tK. 1962. 'fhecfl'ectsoltllrrrirl glarrcl clestnlcti()ll and replncernent therapy on fitr g.t1;11,1|1 i1rnink (r\fu.r1r,1a rl.vrn) uiren a thvrrrrinerfiee cliet. Arn. J. \'et. Res.

2:J:l2l 127.

Rl.-tll-lR, R-.J. 1980. 'I'lte pincal :tncl its lrorrnoncs in the cont()l olreprrrthrctiorr irr nrarnnr:rls. l.rrclrtrine Ro: I : l0-()- IllL

Rr.r,r'!rRr. S. Il., \1. .J. PLRt.()\\, L.'[A]r_\u.Kr)i,,\Nl) I). ci. KLIIN. 1979.,\ <lirrrnal rrrelatonirr rh\ihrn in l.rrirnate cereltxrspinal fluid. Enckrcri-Itokrqv l{).1:21)r i}01.

RIVIt.l.Ll.. .J I.1., Fl R. F-N(;lll-rl,\Rl) 1,,\\t) .J. SoLo\tox.'. l!)77. 'fhe rela.

tiorrslripoItlnrorirrt arrclcrrtisoltothcrnotrltol'thelrarborscalPliorntit ulirut. (,e1. (',rnnp. Ln<krt rinol. ltl ::l-()ll .101.

R()sl.l,.1.,.J. 1..()l-l)I.If.l.l)..\Nl)ll Sl()R-\tSHAK. 1987. Apparenrroleofrrrclalonirr an(l llr(tactin in initilrting rvinter fir qrorrth in rnirrk. (]en.(,orrrp. l..nckrcr irrol. In prcss.

I Sll)R\lsH,\K, .J. ()t.l)Flt]Ll), ANI) .J. AI)AIR. l1)f1,1. lnchrc.

tiorr of rrinler Iirl qrrxvth in rrrink ('\Iusleh z,j.ril) wirh nrel:ttonin. .1.

.'\nirn. Sci. irlJ:ir7 til.,-,A\l)-. l9ti5. fheefIi:ctsof'photo.

ptriorl antl rrrelatonin ()lt sct-ull llrolactin ltlcls of rnink cluring tlrt:lruturlnr rlolt. -J. I)irreul Res. 2:lll ll).

ll()L (;1.()1, .t., D. AI-t-,\lN, ,\Nl) L. NL\RII\El. ll)u,kr. Plrotopcrioclicarrrl honnonitl trlrtrol ol scls<ln:tl co:rt clrangcs in nrarrnttals lithspeci:rl re li'rcnr c lo sheel; turcl rnink. At:ta Zool. Ftrrn. l7l: ll] lU.

l.L. (;. I tlllllAlll.l. .\Nt) l) r\l.t.AI\. l9U.1r. Role of rhe ctrn.porrnrl lrair lirlliclc in il(laptive pelauc r:hanges. Acta Zrxrl. Fenn.l7l:l!) 21.

RL ll. 1.. L., III. l1)81. Frrrlreiuirrq lrrrirnals ol \orth .{rrrerica. (irorrnl'ubl., \erv \'<rrk, \).lt.lllpp.

Rtlsl,(l.(.. I96r-r. IItl'rrron:tl contrrlo1 pclagccvclcsintheslxrt.tailcrlrrr':rscl (,I/rr.i1r1rro nirtru ltuLg.si).()etr. (iourp. l-nrkrrinol.5:222 2ill.

-\Nl) R. K. \l!.\ I-lR. l{)6{). llair cokrr; nrtrlr, arrrl rcsris siTeirr nr:rle, sholt-tailcrl lcasels tleatetl \rith ltrel:rtolrirr. Scienccl(i.-r:1)21 1)22.

.\\r) R. \1. SIL\CK!-I_F()Rtl 1969. !_fIrct ol bLndins onrel)r()(luctive antl pelauc cvt les ir) tlle Ierrct. J. lixp. Zool. 17l:113-117 .

,\\l) R. K. NIllYftR. l96ir. Horrrxrn:rl r:ontnrl ofl)cl:tqc cx les i n tl re rnink.

-f . \larrrrrral. .lti:,:r49 :n)ii.

RYI)1..R, NI. L. lt) t-7. Sc:rsonal colrt chanq-cs in grazirre retl tlccr ((,azl.t&Qhus1..f . Zr x rl. (Lontkrn) lii | : l:37- l.1li.

-

. .\N I) ( ). A. l,l^v( :( )1.N. 11176. A notc on t he eflircr ()l chanqcs intlarlcrrsth on the seasorral rrrxrl grorrth cycle in Soat sheep. Arrirn.I'rrrcl.2ll:?57 260.

.-\\l) S. K. Sl l.l,HI..\S()\. l1)(18. \\kxrl qrrxvth. AcarlcnricI'r ess, \ov \ork, \). 80irpp.

S(lH!.1.1.!lR. \: U. l1)5u. Scals, se:r liotrs, atrrl lalrtrses. Stanfixrl Linir:['r ess, Stanfirrrl, ( )elil. I 7!)p1;.

.\r.-l) r\. \1. .f()ll\S()\. llX;3. \lolt in the norrhernr lirr seal.t:.S. F ish \\'ildl. Sen., SPcc. St i. Rep., F ish. Scr: -150. l31pp.

S(llll\(.Klll., P (;. l1)(jl. Nlitotit activin in rtxrl lirlliclc bulbs. Ausr..f.lliol. Sci. l-1:(iirl) (i{)ll.

S(lll()t--\f,-l)!.R. t'. Fl. \r. \\i\Iilt-RS, R. H(XlK, A\l) 1.. IRVI\(;. l9i)0.llotlr insulation of srrne alctic all(l trolricirl rn:rrrmrnls:irrtl bircls. Iliol.Brrll. l)l):22ir 2iJti.

Sl-.\(;1..1., P ll)7(i. \ftrrpkruencsis of skin. (larnlrrirlsc L,nir'. I)r'ess.( )iulbrirlue, ti.K. 277pp.

:il.\'l,.li-\tl), .1. I I. I9.1rl. Pelaue changes in tlre snorrshot: hare, Lepusa nerica rru.s slru lh oprr.l llangs. .f . \lanrrnal. 2ti:.1 I -tili.

S l.l-N, S. 8., .\N l) R. (i( )N N lll.L. l1)irfJ. \\t< x rl errrvt h in sheep as allectedbv the:rthnirristrati()l) ol certain scr hrnnones. Oan. J. Anint. Sci.3ti::lii- 17.

S()K()1.()\: \: l9{i2. '[']re stnrt:trrre lurcl seasonal variabilitt of'skin inarrrrrclrs (/lnol lonnrl.r I-.). Act:t Bi()1. (lrac()\'. Sen Zrxrl. ir:21)l-r l]02.

S I't .A l{\t-\N, R. l. ( i. l1)77. 'l'lrr sr nr( t ure :r r(l ftl nction 0t tlie lirlly ilevel-optrl Iirllicle. I'aces 121)ll-llJ1!) rn A. -larn'ft, ecl.-['he plrvsiokrgl ancl

PalhrPllsiokrur o[ the skin. \irl. J..{carlerrric Prcss, \et \trrk, NYSI,\lNS, H. .J. l1)71). Prirnetress irr N-orth ,.\rnelic:rrr Iurbearcrs. \\rilcll.

Soc. llull. 7: I 20- I 21.5lI)tll. Fl \1.,.\\t) .1. At).\tR. l9(i9. Irrrhrtrrl earlv firr $orvrh irr pelrer

ruirrk bt liu.lrt regulation. \lrtl. f Lrr'\eivs -11:l(i-20.

.J. ,\l).-\rR. (;. !_. (i()sl t.!t\'. .\Nl) .1. u. ()l.l)r.n.].1). 1969.In<hrtcrl lirr srrrvtlt in rrritrk ll lielrt rcgSrlation. .f..\nirn. Sci. 21):117.(Abstr:)

S I R.\ll.tl. \\l !-. l1)(i.+. -\ stLrclr ol thc hair {irlilcle :urcl irs rncl:rnocytes.l)cr. lli,rl. ll,: lJ-;r,.

'l l\llSJ-\RVt. .1.. \1. NIl.\ll.\l,l\, .\-\.-l) .\. 1.. Sll'l'()t..\. l!)1J.1. '[ he stnrc.Iule iln(l irrsulatiorr properties oI r'eirrrlct:r firr: Ornrrp. Biochcnr. I)hv-siol. 7l),\:(i0 l -(i0!).

'I R.\\'ls. Ii. 1...\Nt) t. l.l. I'll.Bl.-A\1. l{)1J0. Lise ol artilicial liglit arrcl clavIcnslh to altel tlre Iilc or'les ol'nrink. .f. Aninr. Sci.50:I108 I I12.

-l RI,f;1..\Il.tL. t. l!)(i5. IIairrlcnsilt,rrirrclspeetl,artrl he:rt]ossinrnarn,

Iroorlcrl lirt bv rilrrissa <lcrrnal2l'i:211) 2:l(i.

Mll0. Locrrl inter':rctiorrs in rrr;rrrrrrlrli:ur llrir gtrrl th. l);rgesl1)l) 210 ln R. L (i. Spearrnau:rrrrl Il A. Riler: crls. Ihc skin ol rerrc,I rt : rtc'. | . ir rr r. S, ,r . \r rirl r. \er: !.

( )l{t.N l RI..l( lli, N. ll){jl). St alpr hair lepla( cnre rlt in nran. }'ascs 1)1}- lOfJ

itr \\I. Nlorrtaqne;urcl R. L. I)olrson, crls..\clvances irr lriologt ol skirr. IX.ll:rir grrrrrth. ['elg:urrorr I)ress. ()rlirrrl, L'.K.

l).\RAKKAL. P. Ii llXll). I he firre slnrclur(] 0l :rrragerr ]r:rir lirlliclc 01

the rnousr'. I'ages 1.11 -1(i1) ln \\i \lotrt:rgna atrrl R. L. I)obson.ecls. Aclrances irr lriologl ol skirr. lX. I [:rir grrxtlt. ['elg:rrnorr Itre ss,()rlirrrl. U.K.

l1)70. \lorlrlroscncsis ol tlre lrair lirllit lc rlLrrirrg crrregt'n. Z.Zelllixsch. 107: I 7.1- l8{i.

Pr\\\'1.1.1..K. .J. \1., A\l) A. \1. K()RNI..R. l9lJ2. I hc biosr nrlresis of rrlun.rrr.rli.rrr rur.l.rnin. \rl. \r i.7rr: | {{i I l.l.

Pl. l!.RS. R. R.,.{\l) ll..\. It(tKI.R. l1)7fJ. l)rrrlirtrirr an<l sRlrllrIrotttrlre resl)()l1scs t() l)lt()t()l)erio(l in lreilers. !-rrrlotrirrologll0lJ:221) 2i'il.

I)l.ll..RS()N, R.1.. l!)(;(;. I'lte rnanrnrals ()l F.astellt (ltrnrxla. ()xlir|rlf rn ir'. I)ress,'li rri rr rto, ( ) nt. -1(iir 1rp.

I'lNKLrS, Il. l1)51. \[Lrltiple Itairs ([.lcrrtrrrirru.(]ior:rnrrini): rel)()11 ()l'lurr t:rses ol pili rrlrltigcnrini arrcl clisctrssiorr of srrne otlrer arrorrlrliesoI thc pilarvtorrrplex. .f. Irncst. l)('rllrirt()1. l7:2!)l :]01.

Rl.ll), R. N. D. 1978. I lrc elii:cts ol preunarrcv lrn<l lact:rtion on nrolprrr<lrrt tion atrrl livclt'ight in l)oltr:rr tlr errcs..\Lrst..f. I..x1;..A.uric. Atrirn.I lLrslr. llJ:ir8-1i2.

Pelage I'rimine r llltrtlry ct al

rnals. .f . Appl. Phvsiol.20:796-lJ0l.f LIRN flR, ( L lt, .\\ l) .J.

'f. IlAt;NAR\. ll)76. ( ie Irelal ctrclot rinolosr: (itlr

ecl. \\l B. Satrrttlers Oo., I'hilarlelphirr' l'a. 5tX)pp.

t.\l)!.R\\()()l), 1,. S...\Nl) I'. Rl'l\'\()l-l)S. l1)fJ0. I'hotoperiorl artcl firrlcneths in tlte au tic tirx (''11olar lrtgtpus).htt. .l lliortret. 2'1:l]0 'ltl

VtlRIS, ll. .J 11)67. I'he biologv ol tlte stripetl skunk. Ilnir: IllinoisPress, Llrbana, lll. 2 l8pp.

\\:\KI.., \1. fl.. trlitot: 1079. I ltttt:rtl's cotlll)llr:rtl\e \ertcl)rate :lllatolll\'.lJrtl ecl. LiIrir'. (ihicaso Press, (ihicago, Ill.788pp.

\'vr,.lss, D. 1..., 1.. \a s\\lh"s()N. .1. Al)\lR, .J. F.. ()Ll)r'l!l-l). -\Nl) Fl sl()RNISHAK. l1)t10. Plxrtoperioclic cflects rtlt serttltr qlrtcourrticoicls alrtl

firrerorrtlt in nriItk..f. Artirn.Sci. irl:13(i7 1372.

\\jIll l.-\Kt.R, \\i t.., .\Nl) Il. L. [],\KLR ll)'18. lnhibition t>[ hair sr)\\'thbY tlre pcrctttirtrcotts:rltplic:rtirttr ol certaitt atltctral ctn-tital prep:il-a-

tions. Scient c 108:207 201).

,\\l)

-.

l!)irl. ..\ corrrlt:rrisotr of tlte clirect actioIr ttlestroqen arr<l aclrcrral c(trti(lal extncls ott gtrrrvtlt of hair in the rlrt. .f'

lllvesl. L)elrrr:It()1. l7:(il) 77.

\{l II Ml-L\', tI. j. l95ll. 'l'lic c[1ect of aclLelrllectortrv allrl :trlrt:ltocrlli'cal honrrrrtes oIt the hair qrrxr{ll ctclc in tlte ralllrit anrl rat. .f l'.rxltrcrinol. l7:167 17(i.

Wll.l)\t,h-. A. ll. 195'1. 'l'he nricrrstrrpl oI artiIIt:rl tcxtile lll)rcs. \\'ix)lIrxlustrics Res.,\ssoc., Letrls, tlK.

\\'lLS( )N, D. },. ll)u2. \\irlverinc. I'aues (l'1'l {ir52 irr .J. A. Ohal;nraIr ancl

(i. A. Fel<lharner-. ctls. \\iil<l Ittatrlltlals of Nttrtll Attlcrica: l;iolog\', tll:rtr'

aqelnclrt, :lncl ccttttoItt ics. .foh rls I Iopki rls LIr tir'. Itress' lJalt irrtore' \ltl'\{LrRl \lAN, R. .1. l{)80. l he pincal :ts :t ttcttt'oettdocrirre lr:rlls(ltl(tf'

I{osp. Plact. lir(l ):82-1)2.Zl..(,K\\'tlR, l. '1. l1)5i1. 'lhe acceltlratitttl c11ect ol'atlrettltlcctttlttl tttt

reql)wtlr ol' lieil irr tlte thvroitlectolttizecl ra1. l.lltl()crin()l()g\ir2:l]!) '1lJ.

KrI I'lrir,r \\. \\rrrht.)

()R{l t-A\l A. J. \{()Rl HY o};tainql his l}.Sc., NI.Sc., anrl PIr'D. rlcslees lirtrrthe LInivcrsitv ril'(itrelph. I Iis reselrrth illtercsts irtclude the grrru'th alldrlcvckrprrtetrt ttl ttt:triuc tttltttrttrels (1;artitulallr'rrith relert'trcc to thc

Postle;ttrilte periorll, III:lriltc III:ttttltl:tl ellergclics, 'tll(l thc illttl.l( ti.llsiretrvccrr rn:ttitte ttlttrttrt:rls anrl [islrelies. [ [e is cttrrt:tttlr' :r l)osl(loct(n:lln'se:rrtlr ass(xi:Il(' at the l,()Irg \Ilrritre L:rbor:rl(n\, Inslilute ol Nlaritte

St icnces. frnivetsin of (lalilirrrtia S:ult:r(lrttz.

rn

il'lrrto:(lrrrrrrr.\lcrliir(lfill.()rcgorrSlrtlt t nr\ )

.J.\(iK Rosll ()l)t:rinecl lris ll.S. arrtl 1\1.S. tle$'t'ss irt ztxrlttgr firrrrr ()liio StrteUniversitv atrrl his I'li.l). in phtsiolouv lirrtlr ()regotr Slale Lltrivt'rsitr: I'.lltrl!)fl5 t. l!)8{i llc uas al} assistalll Prttfessttr .l z,,l.tl at ()re

F,.tttl State L- lri'rersitl, an<l is cttrrctrllv an ilssistallt llrlrlessor ilt llle L:lli\('rsitv of \\rrrrrring in tlre l)cpattrttettt oI Zrxrlttst lLrlrl Pltlsiologr: Rttstrs ctttletltrcse:r1c| iplcrests arc llte lrtlrttt<lItal rcertlatigrl ttl ttt:tttttrtalialt lll;lstttc\stirrrpl;rntatirrr :rtrtl the site ol atlitttt ol'httllttottes lllat leglllate llililgrol'tlr cvt lt's.

(l)lx{():(l()r1rr).\lc(lii(l( nI.,()rc!l()rrSliLl( t rri\:)

Fltl.ll)RI(lK Sl()R\lstl.\K is prttfi'ssrl'of 1;ltrsiolour at ()regotl State L-lni'

versitr I{e reccivecl his ll.S. ancl NI.S. tlegrees lirrttt \Vashitrctorr Statc I ni'rt'rsitv arxl lris I'h.l) iIt etrckrtrittologr lirrtlt tlle Iirriversin oi \\iscolrsilt(Nlatlisrnr). Srtlrsctltterrtlt hc spettt tltree tellrs as lt rest'arclt phtsiologistlith the L,.S. f)eparlrrtclrt o{ .\srictrltLtrt' irt Beltsvillc, l\lcl. Ilc ltas sentrlon tlre etlitorial lrolrrcl ol lJiologt of Iklrtxltu liott, as trlitor-irr'chitll ol tlre

Iourn.al oJ ArtirtnL Sriou'e, ittrrl as a rtttlttllrtt ol tht: Reptrrrlttttive lliokrgfStrrrlr Section 0l tlre \;rti0ttal Ittslittrtes ol Iltlaltlr. Storttlslrrrk is rtt:tive itr

rcse:rrt h on llotntolte:tctirlu itt cklrtesfit altitrl:tls attcl in rc(cllt teitrs has

invcstiq:(er[ the plrotopcriotlit itrttl ]trrrrlotral cotltrrtl o[ lirr gro*'th inrrrink.

s ilwt$