The fox squirrel is North America's largest tree squirrel, thriving from attics to forests.

Nature · Published 3 October 2026 Swipe more like this →

In short: As the largest tree squirrel in North America, the fox squirrel is a master of adaptation. Whether nesting in a hollow tree or a suburban attic, these agile creatures use specialized physical traits to thrive in diverse environments, from the Great Plains to the urban centers of the United States.

The fox squirrel, or Sciurus niger, is a highly adaptable species native to much of the eastern United States and parts of Canada and Mexico. Its name derives from the ancient Greek words for shade and tail, while its specific epithet refers to its dark coloration. These squirrels are physically robust, measuring up to 30 inches in total length and weighing as much as 2.5 pounds. They possess specialized anatomy, including sharp claws and developed forearm muscles, which make them exceptional climbers capable of leaping 15 feet horizontally.

Unlike many other tree squirrels, the fox squirrel is strictly diurnal and spends significant time foraging on the ground. They are not territorial, yet they maintain a complex social existence, communicating through a variety of vocalizations like chucking and clucking. Their shelters, known as dreys, are either leaf-based platforms for summer or sturdy tree cavities for winter. These dens are often repurposed from woodpecker holes or hollowed out over decades. They are known to be as comfortable in human-made structures as they are in natural forest habitats.

Their diet is remarkably varied, shifting with the seasons and geography. They rely on mast—such as acorns, hickory nuts, and walnuts—but also consume buds, insects, fungi, and agricultural crops. In urban environments, they readily exploit human food sources. While they have few natural predators, their populations are influenced by factors like mange, severe winter weather, and habitat loss. Today, they are found across much of North America, having been introduced to many western states, though they remain absent from much of New England and the Atlantic provinces.

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