Black panther

A black panther is the melanistic color variant of any Panthera species. Black panthers in Asia and Africa are leopards (Panthera pardus) and 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 leopards. One was recorded in the equatorial forest of Cameroon.

...
Wikipedia