Black wildebeest
Where it lives alongside the blue wildebeest, the two species can hybridise, and this is regarded as a potential threat to the maintenance of the species. The black wildebeest was once very numerous and was present in Southern Africa in vast herds, but by the end of the 19th century, it had nearly been hunted to extinction and fewer than 600 animals remained. A small number of individuals was still present in game reserves and at zoos, and from these, the population was rescued.
Black squirrel
Large natural populations of black (eastern gray) squirrels can be found throughout Ontario and in several parts of Ohio, Maryland, Michigan, Houston, Indiana, Virginia, Washington, D.C., Iowa, Wisconsin, Minnesota, Pennsylvania, and Kentucky. Populations of gray squirrels in which the black subgroup is predominant can be found in these six areas as well as in smaller enclaves in Missouri, New Jersey, southern New York, Illinois, Connecticut, and California. Outside areas of North America where black squirrels occur naturally in abundance, there are several notable introduced populations of black squirrels:
In the United States, the city of Kent, Ohio developed a significant black squirrel population after ten were legally imported from Canada in February 1961 by Larry Woodell, the head groundskeeper at Kent State University. They have driven out native squirrels in many areas, though they peacefully coexist with most other rodent wildlife.