Eastern Gray Squirrels

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Eastern Gray Squirrel (Sciurus carolinensis)

An eastern gray squirrel in a tree
An eastern gray squirrel in a tree

Introduction

If you’ve spent any time in a New York City park, chances are you have spotted an eastern gray squirrel (Sciurus carolinensis). These tree-dwelling animals have become something of an unofficial mascot for the city’s parks by nature of their visibility. They can often be seen leaping through wooded areas, chasing other squirrels around tree trunks, or perched on park benches nibbling on nuts and seeds.

The fast pace of city living suits eastern gray squirrels. They use their long tails and sharp claws for balance while climbing, running, and leaping between tree branches—no rush hour traffic or train delays will keep them from getting where they’re going. And the wide variety of food options that New York City offers isn’t lost on them either. They will happily feast on nuts, acorns, seeds, berries, fruit, and anything else they manage to scavenge. 

For many New Yorkers, squirrels are as much a fixture of our parks as the grass, trees, and benches. However, their journey to become one of New York City’s most abundant wildlife species has been a long and challenging one.

Squirrel poking its head out of a hole in a tree.
Squirrels will often build their nests, which are called "dreys," in tree cavities like the one shown here

General Information

Background

During the colonial era, eastern gray squirrels were found throughout New York State in large numbers. The variety of hardwood trees in the region made it an ideal habitat for them. Some areas of New York had so many squirrels during that time that farmers even considered them pests. People would occasionally report seeing large groups of squirrels traveling across the countryside, eating everything in sight. But over time, deforestation and hunting greatly reduced their numbers. And by the mid-1800s, spotting a squirrel in New York City was such a rare occurrence that crowds would sometimes form if one was seen on a city street.

However, in the late 1800s, squirrels were reintroduced to American cities in an attempt to bring more “nature” into urban parks and natural areas. These efforts were ultimately successful, though there were challenges along the way. City-managed culls periodically thinned squirrel numbers through the years. And in the 1870s people began trying to remove them from parks again, believing that squirrels were harming local bird populations. Still, squirrels managed to find a foothold in the city. By the mid-1880s, there were an estimated 1,500 squirrels in Central Park. Today they can be found in parks throughout the five boroughs.

Appearance

Eastern gray squirrels can grow 9 to 12 inches in length and reach two pounds upon sexual maturity. Despite their name, they come in a variety of colors, and will often display a mix of gray, brown, black, and cinnamon fur. Their long-haired, bushy tails can grow to be roughly as long as their bodies.

The squirrel population in North America was once mostly made up of dark-colored squirrels, as darker colors allowed them to remain hidden from birds of prey in the air. However, their dark colors made them more visible from the ground, and much easier for human hunters to spot. As human hunting increased, it is believed that squirrels’ coats grew lighter as an evolutionary defensive response. The light grays and browns that their fur now features keeps them camouflaged from predators both on the ground and in the sky.

Behavior

Gray squirrels reach sexual maturity at 12 months and can mate up to twice a year. One mating season is in late winter, and the other is in mid-summer, depending on food availability. Multiple males chase a female during courtship, with the most dominant male ultimately mating with the female. The young are born blind and hairless. Their eyes begin to open after approximately 28 to 35 days. When they are 42 to 49 days old their furry coats fully develop and they begin to venture from the nest.

Since eastern gray squirrels usually live in trees, they prefer woodland areas that are primarily made up of oak and black walnut trees. Eastern gray squirrels generally live either in dens made in the cavities of healthy trees, or dreys, which are nests made of twigs and leaves that are constructed high up on tree branches. During periods of severe cold, eastern gray squirrels can stay in their dens or nests for several days at a time, only coming out to visit their stores of food. The average life expectancy for an adult squirrel is six years, and the records for maximum lifespan are 12 years in the wild and 20 years in captivity.

An eastern gray squirrel in a tree
An eastern gray squirrel in a tree

Fast Facts

  • Squirrels and other small rodents are hardly ever found to have rabies or transmit them to humans.
  • Eastern gray squirrels can be of human concern when they gnaw on home structures for nesting purposes. Squirrels can also create electrical hazards by chewing on insulation and exposing wires. In 1987, a squirrel gnawed on a power line at the NASDAQ computer center, shutting down stock trading for over an hour.
  • Squirrels will bury or hide their food to eat throughout the winter. The nuts and seeds that were not eaten can end up growing into new trees.
  • Squirrels can run up to 15 mph on the ground and leap upwards of 8 feet.

Coexisting With Squirrels in NYC

  • Keep your distance. Squirrels have sharp teeth and a strong bite. They may mistake your hand for food if you try to pet them or feed them by hand, so admire them from afar.
  • Seal up your home. Squirrels can create nests in attics and roofs. Seal up any holes or potential entry points to prevent them from getting inside.
  • Do not feed. Squirrels are very capable of finding their next meal, and can even store extra food away to eat later. Handouts can endanger squirrels by causing them to lose their ability to search for their own food.