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MELANISM IN BREEDING WILD CATS

I have been interested in genetics in a practical way for many years, and in fact started reading about the subject whilst still a schoolboy, but I would be the last to describe myself as an expert.

It was with some surprise that I found on starting zoo work, in 1972, that considerable confusion existed in the minds of many people, with regard to colour inheritance in cats, primarily with black leopards but closely followed by the white tigers at Bristol Zoo.

As one who travelled half the length of Britain as a fifteen year old, specifically to see the first pair of white tigers at Bristol Zoo, I was probably more interested in them than in black leopards. However as we were more likely to be able to acquire black leopards at Calderpark than white tigers, it seemed logical to concentrate on them. Seven years later, in spite of numerous hints and downright direct approaches, we still haven't been able to winkle a white tiger out of Bristol Zoo, so I was probably right.

My attention was drawn to black leopards in 1972 because, at the time, we had a trio of spotted leopards in our cat house. One pair, every so often in the past had produced a dead black cub amongst their normal spotted litters. Soon after I arrived the female of this pair died of an ectopic pregnancy. It was the attempts to explain why her black cubs were being produced, and that it was not by 'Act of God' chances or first mutations, that started me off on the present line of enquiry.

Black leopards in the wild state are well known, as is the production of black cubs from two spotted parents, or where one parent is black and one spotted. The occurrence of black and spotted cubs in the same litter had also been frequently documented. It seemed to me fairly obvious, although at this stage I had not done any reading on it, that the observations just described immediately suggested that in the black leopard we were dealing with a straight forward recessive factor; and so it turned out.

If you cast your minds back to the situation in British zoos in 1972, the picture was quite different from today's. Breeding results in zoos were only a fraction as good as now. This can be attributed to changed standards of awareness, new and better diets, and much higher expectations on the part of nearly everybody. There was no ABWAK and no Cat Survival Trust, and there were very few small cats. Good young pairs of black leopards were almost impossible to obtain without importing them, and then at very high cost. Dublin and Howletts were breeding them, and Colchester and Jimmy Chipperfield were producing the odd one or two, and that was the lot. Spotted leopards, on the other hand, were plentiful and rapidly approaching the situation which, we find today, of over production.

Then, in a chance conversation with Terry Murphy at Dublin Zoo, he mentioned to me that he had a litter of 3 male and 1 female black leopards. As the males were starting to fight he had separated them but was having difficulty disposing of them as single males. He agreed to give us one, at a listed value of £700, the favour to be returned at a later date.

We immediately set about acquiring three, unrelated, spotted females, in the hopes that one at least might be carrying black as a recessive. We knew that for years Bristol Zoo bad been in the habit of matinq its spotted female, Jenny, to the male of its pair of blacks. All the cubs from this very productive female had been spotted and were distributed throughout British zoos. I was sure our original pair had originated from this pair, and I just hoped we could pick up one or two other females descended in the same way.

Of course, the arrival in a small zoo of four leopards, more or less simultaneously, aroused a lot of comment. It was a considerable relief in 1975, when the first cubs were born, to find the entire litter was black. The first litters from both of the other females were entirely spotted. So, after another litter or two from each, we disposed of these two females.

During this time I had been asked to give an explanation many times. I am indebted to Dr Cohen, of the Genetics Department of Glasgow University, for- drawing my attention to some published work by Ray Robinson, the existence of which I had not suspected. Until then I had not believed that any systematic work had been done, I had been working on the assumption that the confusion existed because of misleading remarks like, 'work at Hanover Zoo has shown that the black colour is due to a dominant gene, probably homologous with dominant black in other forms' (Searle, 1968), or like that of Crandall (1964) that in his experience he had never known of a black cub being born to spotted parents.

An East German publication by Puschmann (1975) states that, 'Two black parents usually produce black cubs'. And Henderson, in his book 'Circus Doctor' published in 1951, states that a black pair may produce spotted young. Eaton (1977) says that this was the only reference to the phenomenon he was able to discover in the literature.

Robinson cleared the matter up conclusively. He contacted 128 zoos known to be breeding leopards and received returns from 72 describing their breeding experiences with the spotted and black forms. He was able to demonstrate quite conclusively that the black form of the leopard con be shown as an autosomal recessive to the spotted. In the interests of brevity, I have, with assistance, shown this in a diagram (see Appendix).

Robinson also found that the average litter size from black females is smaller than that from spotted. He has hypothesised on the reasons for this and discussed the possible significance with regard to the wild distribution of black leopards in parts of South-East Asia . From my own observations and those of our Curator, Lutz Kuschinski, we strongly suspect that inbreeding may have a great deal to do with it.

Many black leopards in Britain are known to be more aggressive and highly strung than spotteds, many of which are almost ridiculously tame. I am ashamed to say that our original male exhibits pronounced stereotyped behaviour patterns such as exaggerated pacing and star gazing, and this seems to have been inherited to a lesser degree by one of his black daughters that we have kept. None of our other leopards ever did this, and they were kept in identical conditions. I feel sure that a lack of understandinq about the genetic possibilities of introducing fresh blood has been a major factor in encouraging the persistence of breeding black to black, often in brother and sister pairs.

I hope the accompanying Appendix will go some way to encouraging people to branch out in a systematic fashion.

Of course, it may have relevance in other directions. Melanism has been recorded in many species of exotic cats, for example: jaguar, puma, serval, lynx, Temminck's golden cat, tiger, Geoffroy's cat and probably others. In these species it is likely to be inherited in the same way as in leopards.

Whilst a black tiger is not everybody's cup of tea, (1 once heard the white tigers at Bristol Zoo described as an abomination of nature) there is no doubt that black jaguars, for example, are. In Britain at the moment there is only one black jaguar, and that is a female recently imported by Marwell. The prices quoted on the continent and in the U.S.A. are ridiculous, at £8,000 or more a pair (although single males cost less than half).

At the same time it is becoming extremely difficult to find good homes for spotted jaguar cubs in this country,

One could say, well so what? What's the point of breeding melanistic specimens? Surely we should be trying to encourage the breeding of more endangered species ? I have considerable sympathy with this point of view. When a melanistic form occurs in nature, as part of the wild population, then there seems to be every justification for trying to breed it. Never- theless when one sees the great scientific and popular interest aroused by the white tigers at Bristol Zoo, and the excitement amongst cat keepers when referring to Marwells black jaguar, it's hard not to feel envious.

Anyway, what would the people present here do if they had bred a lion, as we have done, which, instead of being normally-coloured, was born with a pitch black patch extending the length of the inside front leg and across the chest? Melanism in lions is unknown. The only reference I can find is in June Kay's book 'Okavango' (p.68), which describes a hearsay account of a black lioness in the African bush.

In conclusion; inbreeding amongst black leopards in captivity is so well known that a zoo Director said to me recently 'Ah, but my pair was wild caught'. If the specimens in captivity are to maintain the population into the foreseeable future without the undesirable necessity for reinforcements from the wild state, and this paper helps in any way in maintaining a healthy population, then that's all one can ask.

References
Crandall, L., 1964, The management of Wild Mammals in Captivity. University of Chicago Press.

Eaton, R. L., 1977, Reproductive Biology of the Leopard. Zoo. Garten N F Jena 47 (5) S.329-351 .

Henderson, 1951, Circus Doctor.

Kay, J., -, Okavango,

Puschmann, W., 1975, Wildtiere in Menschenhand, p.321, Saugetiere Berlin.

Robinson, R., 1970, Inheritance of the black form of the Leopard (Panthera pardus)

Robinson, R., 1970, The breeding of black and spotted leopards, J. Bombay Nat. Hist. Soc. 66 (3); 423-429.

Robinson, R., 1978, Colour Inheritance in small livestock. Fur & Feather Publication.

Searle, A.G., 1968, Comparative genetics of Coat Colour in Mammals, p.148, Logos Press.

Ulner, F.A., 1941, Melanism in the Felidae, with special reference to. the Genus Lynx J. Mammal. 22: 285-288.

For other papers from the ABWAK Symposium click here,
For details of Glasgow Zoopark's lion which had partial melanism Click Here