The Eastern Grey Squirrel (Sciurus carolinensis) is a familiar sight across North America, recognized by its predominantly gray fur, often with a brownish tint, and a white underside. Its large, bushy tail is a striking feature. These agile rodents are common in various environments, from dense forests to suburban yards, known for their quick movements and climbing ability.
Lifespan in the Wild
In the wild, Eastern Grey Squirrels have a short lifespan. While some individuals live up to 12 years, the average for an adult is closer to 6 years. Many young squirrels do not survive their first year, with kit mortality rates around 75%. This shorter average is due to constant environmental challenges.
Factors Affecting Survival
Several factors influence an Eastern Grey Squirrel’s survival in the wild. Predation is a threat, with common predators including hawks, owls, foxes, bobcats, raccoons, and domestic cats and dogs. Squirrels use quick movements and tree-climbing to evade dangers, but young squirrels in nests are vulnerable to raccoons and snakes.
Diseases and parasites also affect their survival. Eastern Grey Squirrels can carry ailments like typhus, plague, tularemia, and squirrelpox virus, which can be fatal. Parasites such as mites, fleas, lice, and ticks can infest squirrels, potentially causing secondary infections or transmitting diseases like Lyme disease or Rocky Mountain spotted fever.
Consistent food access is important for their health and survival. Their diet primarily consists of nuts, acorns, seeds, and fruits, which they often bury for later consumption. They may also eat tree bark, buds, and fungi. Fluctuations in “mast” crop availability, particularly nuts, can lead to population declines. Squirrels do not hibernate, relying on stored food and a fat layer to survive winter.
Habitat quality, especially mature trees, impacts their safety and nesting. Tree cavities offer shelter for nesting and predator protection, improving young survival compared to leaf nests. Human activities like vehicle collisions, pest control, and habitat loss also cause squirrel mortality. Extreme weather, such as severe winters or hot summers, affects survival by impacting food availability and increasing dehydration or hypothermia risk.
Lifespan in Human Care
In controlled environments like rehabilitation centers or zoos, Eastern Grey Squirrels live considerably longer. Consistent food, predator protection, and veterinary care remove typical wild challenges. A captive female has lived over 20 years, with some records indicating a maximum of 23.5 years. This contrasts with their wild lifespan, showing the impact of environmental pressures on longevity.