Melanistic leopards are also called black panthers. Pseudomelanism (abundism) also occurs in leopards. Melanism in leopards is inherited as a trait relatively recessive to the spotted form. Interbreeding in melanistic leopards produces a significantly smaller litter size than is produced by normal pairings. The black panther is common in the equatorial rainforest of the Malay Peninsula and the tropical rainforest on the slopes of some African mountains such as Mount Kenya. Between January 1996 and March 2009, Indochinese leopards were photographed at 16 sites in the Malay Peninsula in a sampling effort of more than 1000 camera trap nights. Of the 445 photographs of melanistic leopards, 410 came from study sites south of the Kra Isthmus, where the non-melanistic morph was never photographed. This data suggests the near fixation of the dark allele in the region. The expected time for the fixation of this recessive allele due to genetic drift alone ranged from about 1,100 years to about 100,000 years. Pseudomelanism has also been reported in leopards (Wikipedia).