Leopard Playing With Snow

A melanistic morph of the leopard occurs, particularly in mountainous areas and rain forests. The black color is heritable and caused by recessive gene loci. (While they are commonly called black panthers, the term is not exclusive to leopards; it also applies to melanistic jaguars.)
Melanistic leopards are particularly common on the Malayan Peninsula: early reports suggested up to half of all leopards there are black, but a 2007 camera-trap study in Taman Negara National Park found that all specimens were melanistic. Although the benefits of melanism are difficult to interpret, it may serve as camouflage in the rainforest habitat. Genetic research has found four independent origins for melanism in cats, suggesting there may be an adaptive advantage. Another possibility is that the color variation is a relic adaptation to an epidemic; genes causing melanism can also affect the immune system.
In Africa, black leopards are much less common, as melanism is not an adaptive advantage on the savanna: dark coloration provides poor camouflage and makes hunting difficult. In the dense forests of the Ethiopian Highlands, however, the black leopard is much more common than in Africa generally; as many as one in five leopards may be melanistic.
Pseudo-melanism (abundism) occurs in leopards. A pseudo-melanistic leopard has a normal background color, but the spots are more densely packed than normal and merge to obscure the golden-brown background color. Any spots on the flanks and limbs that have not merged into the mass of swirls and stripes are unusually small and discrete, rather than forming rosettes. The face and underparts are paler and dappled like those of ordinary spotted leopards.