Jaguar Hunts For A Crocodile

The black morph is less common than the spotted form but, at about six percent of the population, it is several orders of magnitude above the rate of mutation. Hence, it is being supported by selection. Some evidence indicates the melanism allele is dominant. The black form may be an example of heterozygote advantage; breeding in captivity is not yet conclusive on this.
Melanistic jaguars are informally known as black panthers, but like all forms of polymorphism, they do not form a separate species.
Extremely rare albino individuals, sometimes called white panthers, also occur among jaguars, as with the other big cats. As usual with albinos in the wild, selection keeps the frequency close to the rate of mutation.