Black squirrels exist, captivating observers with their distinctive dark coats. They are a variation within common squirrel populations, often leading to questions about their species classification.
Understanding Black Squirrels
Black squirrels are not a separate species, but a naturally occurring color variation, known as a melanistic morph, of existing squirrel species. They are most frequently observed as a variant of the eastern gray squirrel (Sciurus carolinensis) and occasionally the fox squirrel (Sciurus niger). Despite their dark fur, these squirrels share the same behaviors, dietary preferences, and typical lifespans as their lighter-colored counterparts.
These melanistic squirrels are omnivores, consuming fungi, seeds, nuts, fruits, insects, eggs, and small animals. Their average lifespan in the wild ranges from one to ten years, typically five to ten years depending on environmental factors. Like other squirrels, they are known for hoarding food and can be quite territorial, adapting well to both natural woodlands and urban environments.
The Genetics of Their Color
The dark coloration of black squirrels results from melanism, a genetic phenomenon involving melanin overproduction. This increased pigmentation is caused by a specific genetic mutation. In eastern gray squirrels, for example, black fur is linked to a deletion in the melanocortin 1 receptor (MC1R) gene, specifically an allele known as MC1R∆24.
For jet black fur, a squirrel typically needs to inherit two copies of this mutated gene, one from each parent. If an individual inherits only one copy of the black gene and one gray gene, its fur may appear brown-black. Research suggests this specific black pigment gene may have originated in fox squirrels and was later transferred to gray squirrels through interspecies mating.
Where Black Squirrels Are Found
Black squirrels are primarily found across North America, with populations in the Northeastern United States and Canada. They are particularly common in the northern parts of their species’ ranges, especially around the Great Lakes Basin, including Ontario and Michigan, where they are often the predominant color morph. While less common overall than gray squirrels, they can be locally abundant in certain urban and suburban environments.
Black squirrels were introduced to the United Kingdom, where they have established populations. Although their numbers account for less than one percent of the total squirrel population in many areas, some regions exhibit much higher concentrations. Historically, black squirrel populations may have been more widespread in North America’s dense, old-growth forests, where their dark coats could have offered a camouflage advantage.