Case Report

Trauma

Int. J. Oral Maxillofac. Surg. 2014; 43: 1459–1464http://dx.doi.org/10.1016/j.ijom.2014.07.006, available online at http://www.sciencedirect.com

Facial injuries following hyenaattack in rural eastern EthiopiaM.J. Fell, Y. Ayalew, F.C. McClenaghan, M. McGurk: Facial injuries following hyenaattack in rural eastern Ethiopia. Int. J. Oral Maxillofac. Surg. 2014; 43: 1459–1464.# 2014 International Association of Oral and Maxillofacial Surgeons. Published byElsevier Ltd. All rights reserved.

Abstract. Hyenas are effective hunters and will consider humans as potential prey ifthe need and opportunity arise. This study describes the circumstances of hyenaattacks, the patterns of injuries sustained, and reconstruction in a resource-poorsetting. As part of a charitable surgical mission to Ethiopia in 2012, 45 patients withfacial deformities were reviewed, of whom four were victims of hyena attacks. Asemi-structured interview was performed to ascertain the circumstances of theattack and the subsequent consequences. The age of the victims at the time of attackvaried from 5 to 50 years. The attacks occurred when the victims were alone andvulnerable and took place in outdoor open spaces, during the evening or at night.The initial lunge was made to the facial area; if the jaws closed on the facial bonesthey were crushed, but in all cases the soft tissues were grasped and torn from theunderlying bone. Reconstruction was dictated by the extent of soft tissue loss butcould normally be obtained by use of local or regional flaps. Hyenas have beenshown to attack humans in a predictable way and cause injuries that typicallyinvolve the soft tissues of the face.

0901-5027/01201459 + 06 # 2014 International Association of Oral and Maxillofacial Surge

M. J. Fell1, Y. Ayalew2,F. C. McClenaghan3, M. McGurk4

1Frenchay Hospital, Bristol, UK; 2MedicalRegiment, Catterick, North Yorkshire, UK;3Department of Surgery, The Royal LondonHospital, Whitechapel, London, UK; 4Maxillo-Facial Surgery, Guy’s and St Thomas’Hospital, London, UK

Key words: hyena; animal attacks; facial in-juries; facial reconstruction; Africa; Ethiopia.

Accepted for publication 15 July 2014Available online 15 August 2014

Spotted hyenas (Crocuta crocuta), hereaf-ter referred to simply as hyenas, are themost common carnivore in Sub-SaharanAfrica, with substantial numbers foundespecially in eastern areas of the conti-nent.1 Hyenas have adapted to survive in arange of habitats including deserts, wood-lands, and mountainous areas, but tend tocongregate in greatest abundance neargame reserves and areas of human settle-ment.8 The two other extant species of thehyena family are the brown hyena(Hyaena brunnea), which is found inSouth Africa, and the striped hyena(Hyaena hyaena), which is found in north-ern Africa and parts of Asia.3

Hyenas are large (45–80 kg) predators,distinguished by exceptionally enlargedpremolars, robust skulls, and heavily mus-cled jaws (see Fig. 1).4 Though historical-ly regarded as pure scavengers, hyenas arein fact effective hunters, with observationstudies showing active hunting to accountfor 60–90% of their food intake.2,8 Hyenasrequire 4 kg of meat per day to maintaintheir condition, but compared to carni-vores of a similar size, they do not exhibita significant preference for prey selectionand have been observed eating speciesranging from fish to buffalo.4 Hyenas willadapt their killing method depending onthe size of prey, with a disembowelling

technique used for larger animals and thetearing away of chunks of flesh from thehead and neck region in small to mediumsized animals.8

The natural environment of hyenas hasbeen altered in Africa by the steady culti-vation of land due to population pressure.This tends to destroy the animals’ naturalhabitat, as is the case in Ethiopia wherethe human population has risen to 90million alongside an estimated 4000–5000 resident hyenas.3,9 Hyenas are tol-erated by humans throughout East Africabecause of their perception as effectivescavengers who willingly remove gar-bage, carrion, and other by-products of

ons. Published by Elsevier Ltd. All rights reserved.

1460 Fell et al.

Fig. 1. The spotted hyena (Crocuta crocuta)at a feeding ritual in the city of Harar in theeast of Ethiopia. The ritual occurred everynight at a location nearby the walls of the cityand consisted of a group of hyenas being fedmeat whilst observed by a group of locals andtourists.

human existence.17 An example of thiscan be seen in the eastern city of Harar ineastern Ethiopia, where hyenas are fed ina ritualistic way that plays a significantpart in the daily routine of the communi-ty.8 However, this symbiotic relationshipis tenuous; hyenas are skilled, unscrupu-lous, and opportunistic predators who willview humans as potential prey in the faceof scarcity.1,10

Brief reports of hyenas attackinghumans in eastern and southern Africancountries over the last two centuries can be

Table 1. Circumstances surrounding the hyena

Case SexAge when

attacked, years

1 Male 5 Playing2 Male 7 Playing3 Female 50 Walkin4 Male 15 Sleepin

guardin

Table 2. The injuries sustained from a hyena atsurgical team.

Case Injuries sustained

1 1. Soft tissue lacerations to midface2. Nasal bone fractures3. Disruption to left medial canthus

2 1. Degloving of scalp2. Soft tissue lacerations to midface3. Disruption of bilateral medial canthu

3 1. Right mandibular ramus fracture(non-united)

2. Laceration to lip4 1. Loss of nasal bones

2. Disruption of right medial canthus

found.1,8,10,16 Lacking in the literature todate is a detailed account of how hyenasattack humans, the patterns of injuriessustained, and the reconstructive methodsavailable to a surgeon faced with theseinjuries.

Methods

Project Harar is a community-based char-ity that co-ordinates surgical treatment inEthiopia; in 2012, the charity embarked ona 6-week mission to Addis Ababa. Anoutreach programme recruited 45 patientsfrom rural regions of eastern Ethiopia withhead, neck, and facial pathologies of vary-ing chronicity, severity, and causes. Allpatients were from low socio-economicbackgrounds and were living in areaswhere transportation constraints and apaucity of secondary and tertiary healthsystems conferred significant barriers toappropriate healthcare.

In this treatment population, fourpatients had been the victims of hyenaattacks and had significant residual facialdeformity. Two had undergone recon-structive surgery on a previous mission.

Using a semi-structured interview, thepatients were questioned about the cir-cumstances of their attack, any immediatecare they had received, and the socialconsequences of the attack. Language bar-riers were mitigated by employing twobilingual interviewers who spoke in Am-

attacks as determined by semi-structured intervie

Situation of attack Vulnera

with other children in a field Smallest chil alone near a field Alone

g with a group on a rural road Slowest runng alone outside whilstg cows

Sleeping alon

tack and subsequent problems faced by the patie

Age atpresentation, years Physical disabili

14 1. Facial scarring2. Epiphora

s

12 1. Facial scarring2. Epiphora3. Dacryoadenitis and

canaliculitis55 1. Facial scarring

2. Compromised mast

45 1. Facial scarring2. Facial pain due to

entering nasal cavi

haric and Oromo. Operations were per-formed at plastic surgery units in AddisAbaba (Yekatit 12 Hospital and the CUREHospital) by a multinational team led byEthiopian plastic surgeons.

Results

The cohort consisted of three males andone female. All four of the patients ini-tially presented to a local hospital foremergency stabilizing treatment. The pre-sentation to the reconstructive surgicalteam occurred at a mean time of 23 years(range 5–30 years) post injury. A summaryof the semi-structured interviews witheach patient regarding the circumstancesof the attack and the injuries sustained aredisplayed in Tables 1 and 2, respectively.

Case 1 was a male patient who pre-sented to the reconstructive team aged11 years, at 6 years after the hyena attack(see Fig. 2). The boy had been attackedaged 5 years by a solitary hyena whilstplaying with a group of other children inthe evening. The jaws of the hyena hadextended across his whole face resulting inloss of the nasal structures, disruption ofthe left medial canthus, and fractures tothe right temporal bone. For reconstruc-tion, the scars around the nose wereopened and the displaced nasal bonesand canthal ligaments were exposed andsutured back into position. The nose wasreconstituted from local soft tissue and the

ws held with the four patients in this study.

bility Time of dayNumber of

hyenas

d in group Early evening SolitarySunset Solitary

er in group Late evening Solitarye Night Solitary

nts when they presented to the reconstructive

ty Psychosocial impact

Subdued mood due to verbalinsults from peers

chronic

Abstinence from school due toverbal insults from peers

icationSubdued mood due to appearanceand eating difficulties

airty

Unemployed due to appearance

Facial injuries following hyena attack 1461

Fig. 2. Case 1. Plate 1 shows the patient at presentation to the first reconstructive team aged 11 years (6 years after the attack). The computedtomography (CT) reconstruction in Plate 2 shows fractures to the right temporal bone and the nasal bones. Plate 3 shows the case at follow-up, 3years after reconstructive surgery.

Fig. 3. Case 2. Plate 1 shows the patient at presentation to the first reconstructive team aged 9 years (2 years after the attack). Plate 2 shows theplanning for operative treatment with a split thickness skin graft applied to the scalp and scar revision. Plate 3 shows the patient at follow-up, 3years postoperatively.

nasal tip taken superiorly to be reattachedto the bridge. Skin grafts were used tocover the right temporal soft tissue defectafter the granulation tissue had beencleaned. The patient came for follow-up3 years later, aged 14 years, and no furthersurgery was performed.

Case 2 was a male patient who presentedto the reconstructive team aged 9 years, at 2years after the hyena attack (see Fig. 3). Theboy had been attacked aged 7 years by asolitary hyena whilst playing alone in a

rural field at sunset. Injuries at presentationincluded a non-healed degloving injury ofthe scalp, bilateral disruption of the medialcanthi, and soft tissue scarring, predominant-ly lateral to the left eye. Operative treatmentincluded a split thickness skin graft appliedto the scalp following cleaning of granula-tion tissue and scar revision. The patientcame for follow-up 3 years later and acanaliculodacryocystorhinostomy was per-formed by an oculoplastic team to repair thedamaged bilateral lacrimal glands.

Case 3 was a female patient who pre-sented to the reconstructive team aged 55years, at 5 years after the hyena attack (seeFig. 4). The woman had been attacked by asolitary hyena whilst walking with a groupof other women on the way back frommarket at dusk. Injuries at presentationincluded a non-united fracture of the rightmandibular ramus and loss of vermillionfrom the right lower lip. The mandibularfracture was repaired with an open reduc-tion and fixation using a bone plate, whilst

1462 Fell et al.

Fig. 4. Case 3. Plate 1 shows the patient at presentation to the reconstructive team aged 55 years (5 years after the attack). Plate 2 shows thefracture being repaired with an open reduction and fixation using a bone plate. Plate 3 shows the patient at 3 weeks postoperative with improvedmastication.

Fig. 5. Case 4. Plate 1 shows the patient at presentation to the reconstructive team aged 45 years (30 years after the attack). Plate 2 shows the nasalreconstruction with the use of a rib graft and a forehead pedicle flap. Plate 3 shows the patient at 4 weeks postoperative once the forehead pediclehad been split.

lower lip competence was restored usingan Estlander flap.

Case 4 was a male patient who pre-sented aged 45 years, at 30 years afterthe hyena attack (see Fig. 5). The patienthad been attacked aged 15 years by asolitary hyena having fallen asleep onthe ground whilst tending his flock ofsheep at night. The main injuries wereto the midface, with obvious loss of nasalbone and cartilage alongside disruption tothe right medial canthus. Nasal recon-struction was achieved with the use of arib graft for nasal bridge support and an

established forehead pedicle flap tech-nique for soft tissue coverage.

Discussion

The four cases in this article provide aninsight into the setting, victim selection,and timing of hyena attacks on humans inEthiopia. The attacks commonly occurredin open, rural areas when the victims werevulnerable and away from the protectionof human habitation. The fact that some ofthe victims were in groups at the time ofthe attack suggests a complete lack of fear

of humans and that perhaps hyenas regardhumans as being below them in the foodchain.2 Each of the four subjects displayedaspects of vulnerability, either because oftheir young age, because they were a slowrunner, or because they were asleep.1,16

Observation studies have shown that hye-nas do not stalk randomly selected prey asbig cats do, but instead observe from closequarters and locate a weakened individualvia their appearance and behaviour.3,4,8

The timings of attacks coincided withdarkened conditions at dusk or at night,which is consistent with the hyenas’

Facial injuries following hyena attack 1463

documented night-time activity and en-hanced nocturnal vision.4,8

The four patients in this cohort pre-sented many years after the attack withvarying degrees of facial deformity andfunctional loss. The pattern of hyena at-tack, however, was similar in all fourcases, where the primary attack was tothe face with extensive soft tissue loss.In addition, the facial bones were crushedbetween the jaws indicating a very widegap that could extend across the face. Theimpression is that the animals made alunge with their mouth open and per-formed a dual manoeuvre of grabbingthe facial skeleton with their jaws andripping away the flesh. The patients inthis cohort all presented late with injuriesthat were difficult to classify, but the netresult was a destructive injury withdegloving of soft tissue. Consequently,the patients reported an array of functionaland psychosocial disability, preventing thepatients from participating normally with-in their rural communities.

The hyena method of attack has simi-larities to that seen in domesticateddogs.11 Dogs tend to focus on the lips,cheek, and nose when attacking humans,known as ‘the central target area’.12 In-variably the lips are torn and tissue lost asthe animal thrashes around its head. Thiskilling method differs from the big catswhich are known to aim for the neck oftheir prey and cause puncture wounds withthe objective of severing the jugular veins.Proprioceptors on the tips of the teeth ofbig cats enable them to detect bone andalign their jaws sufficiently so that theirteeth can bisect the vertebrae and sever thespinal cord.14

Reports of animal bites from the USAand Germany, consisting mainly of do-mestic cat and dog bites, show that thevast majority of patients sustain superficialwounds only, with bony injuries being ararity.7,11 This is in stark contrast to thepatients in this study, all four of whomsustained significant soft tissue loss, withbony damage in half of the cases. Thegreater degree of damage caused by thehyenas can be attributed to several char-acteristics that enable them to exert hugeforces through their jaws. These include alarge body size, simplified robust denti-tion, complex tooth enamel, and vaultedforehead.13 The long, thick neck providesa highly muscular structure that comple-ments the powerful cutting and rippingmovements of the massive jaws, whichare sufficiently powerful to generate enor-mous bite forces.5 Wroe et al.15 haveproduced average dimensions of hyenaskulls and calculated estimated bite

forces: basal skull length 23.64 cm, skullwidth at zygoma 16.73 cm, estimatedbody mass 69.1 kg, canine bite force773 N, bite force quotient 117.

The management of the soft tissue in-juries was related to the release of scartissue and introduction of new soft tissuewhen required to gain soft tissue coverage.Techniques included split skin grafts whenthe scalp had been lost, an Estlander flapfor lip defects, a forehead flap for nasalreconstruction, and rib grafts to repairmandibular defects. Microvascular repairis possible in this resource-poor setting,but is prone to higher postoperative com-plication rates, therefore simpler techni-ques were preferred.6 Bony defects insome circumstances consisted of impactedor missing bone units, in which case theywere masked with soft tissue cover ratherthan being reconstructed. Alternatively,bone units that were displaced were repo-sitioned when it was judged important toreturn function or aesthetics.

The experience gained from our workwith these injuries is that treatment has tobe individualized to the patient and theirparticular deformities. In acute animal biteinjuries, attention is focused towards com-bating infection and conserving as muchtissue as possible. The patients in thiscohort all presented late and thereforerepresented a reconstructive challenge be-cause loss of soft tissue was universal. Thetissues had healed, so rather than infectionbeing an issue, restoring function becamethe focus of attention. This was achievedby removing obstructive scar tissue andintroducing new soft tissue in a balancedand least invasive way. The bony injurieswere almost an incidental finding and werereconstructed only if necessary.

There were limitations regarding themethod of data collection for this study.The attacks had occurred many years be-fore, giving rise to potential recall bias.There were language barriers with somepatients due to the various dialects used bythe communities of eastern Ethiopia,resulting in communication constraints.This report is further limited because ofthe small sample size of the patients de-scribed and the nature of their recruitment.To get a better idea of the extent of theproblem in Ethiopia it would be useful tocontact each rural hospital, clinic, andhealth post and examine their admissionrecords or conduct retrospective studies.

In summary, the hyena is an opportu-nistic predator and considers humans partof its food chain when the appropriatecircumstances arise. Attacks may be morefrequent in the eastern part of Ethiopiathan in other areas of Sub-Saharan Africa

due to the close proximity in whichhumans and hyenas reside. The animalstend to find opportunities to attack humansat dusk, targeting isolated or vulnerableindividuals. The injuries are predictableand distinguished by the biting then tear-ing away of soft tissue. Much in the sameway as the domestic dog, the target iscommonly the face, but the injuries aremade more extensive by the size andpower of the hyena. Reconstruction hasto be tailored to the individual, but fre-quently requires restoration of soft tissue.

Funding

None.

Competing interests

Professor Mark McGurk is a trustee for theProject Harar Charity.

Ethical approval

Not required.

Patient consent

Granted.

Acknowledgements. The authors wouldlike to thank the staff at Project Hararfor organizing and supporting the facialreconstructive project in Ethiopia. Wethank the staff linked to the Ethiopianorganizations attributed to the project:Yekatit 12 Hospital, CURE Hospital,and the Cheshire Rehabilitation Centre.

References

1. Abay GY, Bauer H, Gebrihiwot K, Deckers

J. Peri-urban spotted hyena (Crocuta cro-

cuta) in northern Ethiopia: diet, economic

impact, and abundance. Eur J Wildl Res

2011;57:759–65.

2. Cooper SM, Holekamp KE, Smale L. A

seasonal feast: long-term analysis of feeding

behaviour in the spotted hyaena (Crocuta

crocuta). Afr J Ecol 1999;37:149–60.

3. Gade DW. Hyenas and humans in the Horn

of Africa. Geogr Rev 2006;96:609–32.

4. Hayward MW. Prey preferences of the spot-

ted hyena (Crocuta crocuta) and the degree

of dietary overlap with the lion (Panther leo).

J Zool 2006;270:606–14.

5. Holecamp KE, Smith JE, Strelioff CC, Van

Horn RC, Watts HE. Society, demography

and genetic structure in the spotted hyena.

Mol Ecol 2012;21:613–32.

6. Huijing MA, Marck KW, Combes J, Mizen

KD, Fourie L, Demisse Y, Befikadu S,

McGurk M. Facial reconstruction in the

1464 Fell et al.

developing world: a complicated matter. Br J

Oral Maxillofac Surg 2011;49:292–6.

7. Kesting MR, Holzle F, Pox C, Thurmuller P,

Wolff KD. Animal bite injuries to the head:

132 cases. Br J Oral Maxillofac Surg

2006;44:235–9.

8. Kruuk H. The spotted hyena: a study of

predation and social behaviour. Chicago:

University of Chicago Press; 1972.

9. Leykun A. The challenges of conserving

Ethiopian wildlife: overview. Walia

2000;21:56–61.

10. Mitchell KB, Kotecha VR, Chandika A.

Bush animal attacks: management of com-

plex injuries in a resource-limited setting.

World J Emerg Surg 2011;6:43–7.

11. Patronek GJ, Slavinski SA. Animal bites. J

Am Vet Med Soc 2009;234:336–45.

12. Stefanopoulos PK. Management of facial

bite wounds. Oral Maxillofac Surg Clin

North Am 2009;21:247–57.

13. Tanner JB, Dumont ER, Sakai ST, Lundrigan

BL, Holecamp KE. Of arcs and vaults: the

biomechanics of bone-cracking in spotted

hyenas (Crocuta crocuta). Biol J Linn Soc

2008;95:246–55.

14. Wiens M, Harrison P. Big cat attack—a case

study. J Trauma 1996;40:829–31.

15. Wroe S, McHenry C, Thomason J. Bite club:

comparative bite force in big biting mammals

and the prediction of predatory behaviour in

fossil taxa. Proc Biol Sci 2005;272:619–25.

16. Yirger G, Bauer H. Livestock depredation of

the spotted hyena (Crocuta crocuta) in

southern Tigray, northern Ethiopia. Int J

Ecol Environ Stud 2010;36:67–73.

17. Yirger G, De Longh HH, Leirs H, Gebrehi-

wot K, Deckers J, Bauer H. Adaptability of

large carnivores to changing anthropogenic

food sources: diet change of spotted hyena

(Crocuta crocuta) during Christian fasting

period in northern Ethiopia. J Anim Ecol

2012;81:1052–5.

Address:Matthew John FellThe GrangeGrange LaneNorth KelseyLincolnshire LN7 6EZUKTel: +44 07879 417795E-mail: mattfell@doctors.org.uk