Squirrels are a common sight across many landscapes, often observed foraging in yards and parks or scampering through trees. Their varied appearances, from familiar grays to striking blacks and distinctive reds, frequently spark questions about their relationships and interactions. Understanding the differences between these squirrel types helps clarify how they coexist in shared environments.
Are Black and Red Squirrels Different Species?
Despite inhabiting similar areas and sometimes displaying comparable behaviors, black squirrels and red squirrels are indeed distinct species. Black squirrels are a color variation, or “morph,” of the Eastern Gray Squirrel (Sciurus carolinensis). This means a black squirrel is fundamentally the same species as a gray squirrel, only differing in fur color. In contrast, red squirrels in North America are typically the American Red Squirrel (Tamiasciurus hudsonicus), which belongs to a different genus entirely. The American Red Squirrel is smaller in size, usually measuring between 11 and 14 inches long, compared to the Eastern Gray Squirrel’s 16 to 20 inches.
The Genetics Behind Black Fur
The black coloration observed in some Eastern Gray Squirrels results from a genetic mutation known as melanism. This phenomenon involves an overproduction of melanin, the pigment responsible for dark coloration in fur and skin. If an Eastern Gray Squirrel has two copies of the gene responsible for gray fur, it will be gray. However, if it possesses one or two copies of the mutated gene, its fur will appear black. A squirrel with one black gene and one gray gene may appear brownish-black, while two copies of the black gene result in a jet-black coat. This genetic variation is a natural occurrence within the Eastern Gray Squirrel population, not an indication of a separate species.
Mating Behavior and Hybridization
Given that black squirrels are simply a color variant of the Eastern Gray Squirrel, they readily mate with other Eastern Gray Squirrels, regardless of their fur color. Their offspring can display either black or gray fur, depending on the genetic inheritance from both parents. However, American Red Squirrels and Eastern Gray Squirrels (including their black morphs) do not naturally interbreed to produce viable, fertile offspring. They are distinct species with different genetic makeups and reproductive behaviors, making successful hybridization unlikely.
Geographic Distribution and Interaction
Eastern Gray Squirrels, including their black variants, are native to eastern and midwestern North America, ranging from southern Canada down to Florida and west to Texas. They typically inhabit mature deciduous and mixed forests, particularly those rich in nut-producing trees like oaks and hickories, and are also common in urban and suburban areas. American Red Squirrels, on the other hand, are widely distributed across most of Canada, Alaska, the Rocky Mountains, and the northern half of the eastern United States. They primarily prefer coniferous forests, feeding heavily on seeds from trees such as spruce, fir, and pine. While there are areas where the ranges of Eastern Gray Squirrels and American Red Squirrels overlap, particularly in mixed forests, their distinct species status prevents interbreeding. This overlap allows for visual encounters but does not lead to reproductive mixing.