MUTANT BIG CATS - BLACK LIONS

Mutants are natural variations which occur due to spontaneous genetic changes or the expression of recessive (hidden) genes. Recessive genes show up when there is too much inbreeding. White tigers and white lions are uncommon in the wild as they lack normal camouflage. Albinism (pure white), chinchilla (white with pale markings) and melanism (black) are the commonest mutations. Erythristic (red), leucistic (partial albinism/cream) and maltesing (blue) are also been reported. Sometimes the markings are aberrant e.g. too sparse or too heavy (abundism), giving the appearance of a pale or dark individual. White, black, red, blue or cream mutations are similar to those found in domestic cats. Sometimes the pattern is different from normal e.g. the blotched King Cheetah or an normally coloured individual may have anomalous black patches (mosaicism) or white patches (partial albinism). Rufism refers to the richness of the red colour in tawny-coated cats.

As well as anomalous colours, there are abnormally large or small individuals, longhaired individuals, short-tailed or even tail-less individuals. All of these occur in domestic cats so why are they less common in big cats? Wild cats displaying these traits may be less likely to survive to pass on the traits. In captivity, humans control which traits are bred, hence the multitude of domestic cat colours and types. In the wild, nature selects against any trait which does not enhance the animal's survival chances.

In the past, the obvious reaction to any unusual big cat was to shoot it for the trophy room. As a result, many interesting mutations may have been wiped out before the genes were passed on. Some colour mutations which would disadvantage a wild big cat are bred in captivity and are not viable in the wild. It is questionable whether these mutants should be perpetuated for the sake of curiosity or aesthetics alone.

Some of the historical information here may also be found in "Mystery Cats of the World" and assorted articles by Karl Shuker. I am grateful to Paul McCarthy and Mary Ann Howell for researching and providing extensive material, information and corrections on white lions and white tigers and to Kevin Chambers of the Zoological Animal Reproduction Center for further information on white lions.

BLACK LIONS

There is a mid 19th century report of a very large "black" Persian lion seen by the archaeologist Sir Henry Layard; he described it as "very dark brown in colour, in parts almost black." Lions are no longer found in that region. This may have been related to the Barbary lion (now extinct in the wild) which is larger than African lions and famed for their extensive black manes stretching from chest to groin.

A partly black lion was born at Glasgow (Scotland) zoo, but was infertile. His colour was probably due to somatic mosaicism (abnormal skin cells). The lion had a pitch black patch extending the length of the inside front leg and across the chest. Somatic mosaicism causes some patches of skin to develop abnormal pigmentation. This anomaly also occurs in domestic cats and accounts for some of the few fertile tortoiseshell male cats.

Called "Ranger" (he was sponsored by Glasgow Rangers Football Club), he was born at Glasgow Zoo in about 1975, the offspring of some lions acquired from Manchester's Belle Vue Zoo. At birth, the lion exhibited a melanistic patch which stretched from his right paw, all the way up the inside of his leg and across his chest. It was believed to be the first time melanism, even partial melanism, had been recorded in the African lion (apart from anecdotal cases). Ranger , frequently mated but failed to impregnate a proven fertile female. Zoo staff believed he had a chromosome abnormality. Ranger was put to sleep in 1997 and sent for post mortem at Glasgow Vet School. It was hoped that blood samples would allow testing for chromosome abnormality, but it was not possible to get testable blood samples. It would have been sensible to analyse tissue samples from the black area and golden area. A sample of testicular tissue should very definitely have been tested!

The pathologist believed that the melanistic patch was similar to that sometimes seen in domestic cats and which also results in sterility. This is a fallacy - it is not the melanistic patches which cause sterility in domestic cats! Black patches caused by chromosome abnormalities can cause sterility. Black patches caused by localised mutation of skin cells have no effect beyond the affected cells though possibly Ranger's mutation also affected internal tissues, included the testes. Localised mutations aren't hereditary unless the testes are also affected. If the testes were affected then Ranger might have sired black cubs instead of golden ones. If Ranger had been fertile and his trait had been hereditary then the zoo could have bred black lions (and possibly tortie female lions). After all, black leopards and black jaguars are always crowd pullers!

Black lions, chocolate brown lions and reddish brown lions have been reported. A very dark brown, almost black lion was reported in Persia (Iran) and a black lioness was reported in the African bush (Okovango). There have even been reports of whole prides of dark brown or black lions; prides comprise closely related lionesses therefore this could be a familial trait. Genetically, lions are spotted cats (residual spots can be seen on tawny lions on the limbs and sometimes on the body) and it's possible that excessively spotted cubs (abundism) might grow into adults with a sooty cast on the fur.

Not a black or chocolate lion, simply a lioness partially silhouetted. Many reports of black lions (and other black big cats) are due to observation in either poor light or with strong sunlight behind the cat.

In May 2008, large black lions were alleged to be roaming the streets of Matsulu township outside the Mpumalanga capital in South Africa. Residents made anonymous phone calls to the Mpumalanga Tourism and Parks Agency (MTPA) about "black lions" that had supposedly escaped from the neighbouring Kruger National Park. While the MTPA took the phone calls seriously, no lions were found by officials sent to search the area and it is believed these were tawny lions seen in poor light or at night when they might appear black. According to a news report titled "Black lions terrify township": Big black lions are said to be roaming the streets of Matsulu township outside the Mpumalanga capital, terrifying residents who say they are too afraid to walk outside at night. Residents have been making anonymous phone calls to the Mpumalanga Tourism and Parks Agency (MTPA) about “black lions” that have escaped from the neighbouring Kruger National Park, said MTPA spokesperson Jimmy Masombuka on Thursday. “We have been receiving these calls from frightened residents who tell us that they spotted black lions prowling the area .... It is surprising for us to hear of black lions. But, although it’s hard to believe, you don’t just dismiss these kind of things. Maybe we are sitting on a great discovery,” he said. Masombuka said some people who said they had seen may have mistaken the dark brown colours for black, or perhaps they had seen the lions at night.".

An image of a white lion posted at cutehomepets.com was transformed into a black lion by "PAulie-SVK" and posted at deviantart.com in 2012. The "black lion" photo has since spread around the internet accompanied by claims that it is a genuine melanistic lion.

The multitude of "Black Lion" pubs in Britain is sometimes cited as evidence for historical occurrences of black lions. However there are also plenty of "blue lion" and "red lion" pubs - the lions depicted originally being heraldic devices (generally a lion rampant).

USEFUL GENETIC TERMS

Textual content is licensed under the GFDL.

For more information on the genetics of colour and pattern:
Robinson's Genetics for Cat Breeders & Veterinarians 4th Ed (the current version)
Genetics for Cat Breeders, 3rd Ed by Roy Robinson (earlier version showing some of the historical misunderstandings)
Cat Genetics by A C Jude (1950s cat genetics text; demonstrates the early confusion that chinchilla was a form of albinism)

For more information on genetics, inheritance and gene pools see:
The Pros and Cons of Inbreeding
The Pros and Cons of Cloning

For more information on anomalous colour and pattern forms in big cats see
Karl Shuker's "Mystery Cats of the World" (Robert Hale: London, 1989 - some of the genetics content is outdated)

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