H U S B A N D R Y AND ZOOS

The white Lowland gorilla

at Barcelona Zoo Gorilla g. gorilla

A N T O N I O J O N C H Director, Parque Zoologic0 de Barcelona, Spain

On I October 1966 Barcelona Zoo’s Centro de Adaptacion y Experimentacion de Ikunde in Spanish Guinea acquired a white Lowland gorilla Gorilla g. gorilZa from the equatorial forest of Nko, near the River Campo, Spanish Guinea.

The gorilla was a male, about two years of age. Morphologically it was normal except that it was white, skin and hair both being completely devoid of pigmentation. The eye had a bluish sclerotic, a normal cornea, and a light blue iris which was very transparent to transillumination. Accom- modation and refraction were normal. The media were transparent and the fundus of the eye normal and totally depigmented. The choroidal vessels were perfectly visible and the pupil was normal. The animal displayed marked photophobia, which caused it to close its eyes repeatedly when exposed to bright light; in diffuse light, similar to that in its biotope, we calculated that it blinked on an average of 20 times a minute.

At the time of capture its weight was 8.75 kg and its measurements were as follows: circum- ference of chest 54cm; length of head and thorax, measured from the back, 47 cm; length of hand and arm (extended) 42 cm; length of foot and leg 40 cm. The gorilla possessed a complete set of milk teeth, which appeared to be in good condition.

It was given the name ‘Nfumu’, which in the Pamu6 language means white.

On checking the literature regarding anomalies in pigmentation of primates, not a single case of albinism in gorillas was found. The Ikunde Centre has, however, recorded several cases of limited albinism in gorillas. These were charac- terised by an absence of pigmentation, usually insignificant, in one area of the skin, always on the hands or feet. This anomaly disappears as the animal develops. We have been told by Sr Curbelo of Bata (pers. comm.) that some years ago a young gorilla was found which had a large un- pigmented area on the head and neck, while the rest of its body had the usual colouration.

Variations in the pigmentation of primates are

not very frequent. Schultz (1956), in a study of the teratology of primates, refers to cases where total albinism in Loris, Cercopithecus, Colobus and Presbytic were recorded. Malbrant and Maclatchy (1949) in their popular work on the fauna of the former French West Africa, describe a case of incomplete albinism in a mangabey Cercocebus torquatus. Our assistant, Juan MasiC, tells us that in the Muni area a completely white Black-and-white colobus monkey Colobus polykomos satanas was caught in 1958 and its skin was kept for several months.

The folklore of the natives (the Fang) of the River Muni and the Cameroons is particularly concerned with gorillas, yet it does not contain a single reference to albinism. On the other hand, the Yebokon clan (Fang) has an albino chimpanzee Pan troglodytes as a totem or guardian, and this figures in their mythology under the name of Nfumu. A D A P T A T I O N OF A L B I N O GORILLA TO C A P T I V I T Y As regards adapting the albino gorilla ‘Nfumu’ to captivity, its rate of adaptation was compared with previous observations made on newly- caught or newly-arrived young gorillas. These have been found to vary according to the age of the animal. When gorillas are caught or purchased by the Ikunde Centre, their ages range between two months and four years, and according to our observations there are three different patterns in the rate of adaptation to captivity. The first is for animals aged from two to 12 months; the second for those between one and two years; and the third for those from two to four years old. It is this last group which we are concerned with at present.

One set of observations concerns the adaptation of a young gorilla to the new diet imposed by captivity. A series of foods is listed in order on a scale of acceptability, and numbered from one to 20. The series starts with Aframomum and is followed by Musanga, Costus, banana, and so on. Number 7 is milk, followed by bread and then finally meat (flavoured but never raw).

H U S B A N D R Y AND ZOOS ‘97

In the case of the albino gorilla it soon accepted milk, jumping the normal order of acceptance, and on the 15th day it accepted bread and biscuits. Normally, bread and biscuits are not accepted by young gorillas of this age group until the 30th to 35th day, and milk on the 8th to 12th day. Some gorillas never accept it.

Another set of observations on the adaptation to captivityof young gorillas keptat the Ikunde Centre is concerned with the animal’s reactions to human beings. Various types of reaction are numbered in sequence from one to 13 and the observer then records the days on which the reactions are noted. As with the observations on the young gorilla’s rate of adaptation to new foods, the behavioural obser- vations are plotted on a graph. Number I I reads: ‘Outside the cage the animal will follow you, even though you do not have any food in your hands; it is possible to take the animal by the hand and it will then accompany you; it will accept direct contact with people known to it and is not aggressive towards strangers.’ Not until it reaches this point can the young gorilla be said to have adjusted to captivity. The albino gorilla crossed this theoretical line on the 15th day, when normally it is only crossed after 30 to 50 days. Only one other young gorilla, a female, crossed this line after a period similar to Nfumu.

As the age of the-animal increases, so it takes longer to reach this point, until finally, with mature male animals, adaptation becomes im- possible. This has already been noted by Schaller (1963), who refers to the great difficulty which was experienced at the experimental station of Tschibati, Congo, in changing the food habits of a gorilla which was nearly adult. It was more than a year before it would accept bread, and it would never allow itself to be touched.

The gorilla Nfumu has been a very forward animal, both in the process of adaptation to the new diet imposed by captivity, and in the process of adaptation to contact with people. It has adapted to a new diet and to contact with people much more rapidly than any other young gorilla observed at the Ikunde Centre.

It is possible that, because of its appearance, the young albino gorilla was not fully accepted by other members of the family group in the wild; and it is also possible that a visual deficiency decreased its optical powers, which could have also made it less acceptable to the group. These

circumstances could have made it specially sensitive to demonstrations of affcction and attention.

Among the negro population of the River Muni there is only one case of total albinism per 10,000 of the population. This figure is probably the same throughout the forest areas of Africa. In the Sudanese region, however, the proportion is even smaller, probably because there are far fewer albinos in the Nilotic group.

The albino gorilla Nfumu is without doubt the only case of albinism in a gorilla that has been recorded. Among chimpanzees there have been cases of partial albinism, but here too no case of total albinism is known.

After the preliminary period of adjustment to captivity at the Ikunde Centre, the albino gorilla was sent to Barcelona Zoo. Since it has been at the zoo, one of its most noticeable characteristics has been the great need for affection displayed in all its actions and reactions. I t shows a great liking for its keeper, with constant manifestations of affection; and it displays jealousy and anger if the keeper acts affectionately towards other animals or people. These manifesta- tions of jealousy consist of scratching and biting a young black gorilla with which we keep it.

Its diet is very varied and ranges from a large proportion of fruits and vegetables to different forms of meat, which it likes very much.

Its growth curve and weight increase are progressing normally and in the s ix months since its arrival at the zoo its weight has increased to 15 kg. It is lively and high-spirited, indicating that it has adjusted successfully to captivity.

I t is hoped that having survived this initial period it will live to maturity and by breeding from it, this mutation will persist since albinism is a recessive character, transmitted exclusively through the father.

REFERENCES S C H A L L E R , G . R . (rg63):iThe Mountaingorilla, ecology and behauiour. Chicago and London: University of Chicago Press. M A L B R A N T , R . and MACLATCHY, A . (1949): Fame de l’equateur africain franpis. Paris: Paul Le- chevalier. S C H U L T Z , A . H . (1956): The occurrence and fre- quency of the pathological and teratological conditions and of twinning among non-human primates. In Hofer, H., Schultz, A. H. and Starck, D., Primarologie: 965-1014. Bale and New York: Karger.