A black panther is typically a melanistic colour variant of any Panthera species. Black panthers in Asia and Africa are leopards (Panthera pardus). Black panthers in the Americas are black jaguars (Panthera onca).
Melanism in the jaguar (Panthera onca) is conferred by a dominant allele, and in the leopard (Panthera pardus) by a recessive allele. Close examination of the color of these black cats will show that the typical markings are still present, but are hidden by the excess black pigment melanin, giving an effect similar to that of printed silk. This is called “ghost striping”. Melanistic and non-melanistic animals can be littermates. It is thought that melanism may confer a selective advantage under certain conditions since it is more common in regions of dense forest, where light levels are lower. Recently, preliminary studies also suggest that melanism might be linked to beneficial mutations in the immune system.
The Javan leopard was initially described as being black with dark black spots and silver-grey eyes.
Black leopards are common in the equatorial rainforest of Malaya and the tropical rainforest on the slopes of some African mountains such as Mount Kenya. They are also common in Java, and are reported from densely forested areas in southwestern China, Myanmar, Assam and Nepal, from Travancore and other parts of southern India where they may be more numerous than spotted panthers. One was recorded in the equatorial forest of Cameroon.
Melanistic leopards are the most common form of black panther in captivity and they have been selectively bred for decades in the zoo and exotic pet trades. According to Funk and Wagnalls’ Wildlife Encyclopaedia, captive black leopards are less fertile than normal leopards, with average litter sizes of 1.8 and 2.1, respectively. This is likely due to inbreeding depression.
In the early 1980s, Glasgow Zoo acquired a 10-year-old black leopard, nicknamed the Cobweb Panther, from Dublin Zoo. She was exhibited for several years before being moved to the Madrid Zoo. This leopard had a uniformly black coat profusely sprinkled with white hairs as though draped with spider webs. The condition appeared to be vitiligo; as she aged, the white became more extensive. Since then, other “cobweb panthers” have been reported and photographed in zoos.
In jaguars, the melanism allele is dominant. Consequently, black jaguars may produce either black or spotted cubs, but a pair of spotted jaguars can only produce spotted cubs. Individuals with two copies of the allele are darker (the black background colour is more dense) than ones with just one copy, whose background colour may appear to be dark charcoal rather than black.
The black jaguar was considered a separate species by indigenous peoples. W H Hudson wrote,
“The jaguar is a beautiful creature, the ground-colour of the fur a rich golden-red tan, abundantly marked with black rings, enclosing one or two small spots within. This is the typical colouring and it varies little in the temperate regions; in the hot region the Indians recognise three strongly marked varieties, which they regard as distinct species – the one described; the smaller jaguar, less aquatic in his habits and marked with spots, not rings; and, thirdly, the black variety. They scout the notion that their terrible “black tiger” is a mere melanic variation, like the black leopard of the Old World and the wild black rabbit. They regard it as wholly distinct, and affirm that it is larger and much more dangerous than the spotted jaguar; that they recognise it by its cry; that it belongs to the terra firma rather than to the water-side; finally, that black pairs with black, and that the cubs are invariably black. Nevertheless, naturalists have been obliged to make it specifically one with Felis onca [Panthera onca], the familiar spotted jaguar, since, when stripped of its hide, it is found to be anatomically as much like that beast as the black is like the spotted leopard.”
A black jaguar named “Diablo” was inadvertently crossed with a lioness named “Lola” at the Bear Creek Wildlife Sanctuary in Barrie, Ontario, Canada. The offspring were a charcoal black jaglion female and a tan-coloured, spotted jaglion male. It therefore appears that the jaguar melanism gene is also dominant over normal lion colouration (the black jaguar sire was presumably carrying the black on only one allele). In preserved, stuffed specimens, black leopards often fade to a rusty colour but black jaguars fade to a chocolate brown colour.
There are no authenticated cases of truly melanistic cougars (pumas). Melanistic cougars have never been photographed or shot in the wild and none has ever been bred. Unconfirmed sightings, known as the “North American black panther”, are currently attributed to errors in species identification by non-experts, and by the memetic exaggeration of size. Black panthers in the American Southeast feature prominently in Choctaw folklore where, along with the owl, they are often thought to symbolize Death.
In his Histoire Naturelle (1749), Georges-Louis Leclerc, Comte de Buffon, wrote of the “Black Cougar”:
“M. de la Borde, King’s physician at Cayenne, informs me, that in the [South American] Continent there are three species of rapacious animals; that the first is the jaguar, which is called the tiger; that the second is the couguar [sic], called the red tiger, on account of the uniform redness of his hair; that the jaguar is of the size of a large bull-dog, and weighs about 200 pounds [90 kg]; that the cougar is smaller, less dangerous, and not so frequent in the neighbourhood of Cayenne as the jaguar; and that both these animals take six years in acquiring their full growth. He adds, that there is a third species in these countries, called the black tiger, of which we have given a figure under the appellation of the black cougar. The head is pretty similar to that of the common cougar; but the animal has long black hair, and likewise a long tail, with strong whiskers. He weighs not much above forty pounds [18 kg]. The female brings forth her young in the hollows of old trees.”
This “black cougar” was most likely a margay or ocelot, which are under 40 pounds (18 kg) in weight, live in trees, and do have melanistic phases.
Another description of a black cougar was provided by Thomas Pennant:
“Black tiger, or cat, with the head black, sides, fore part of the legs, and the tail, covered with short and very glossy hairs, of a dusky colour, sometimes spotted with black, but generally plain: Upper lips white: At the corner of the mouth a black spot: Long hairs above each eye, and long whiskers on the upper lip: Lower lip, throat, belly and the inside of the legs, whitish, or very pale ash-colour: Paws white: Ears pointed: Grows to the size of a heifer of a year old: Has vast strength in its limbs.– Inhabits Brasil and Guiana: Is a cruel and fierce beast; much dreaded by the Indians; but happily is a scarce species.”
According to his translator Smellie (1781), the description was taken from two black cougars exhibited in London some years previously.