The gray squirrel, Sciurus carolinensis, is a highly adaptable omnivorous rodent commonly found across various environments, from dense woodlands to urban parks. Its diverse diet allows it to thrive by consuming a wide range of available food sources.
Natural Foraging Habits
In their natural woodland habitats, gray squirrels primarily forage for plant-based foods. Their diet largely consists of nuts, including acorns, walnuts, pecans, and hickory nuts. They also consume various seeds, such as those from maple, pine, and sunflower plants. Fruits and berries, like wild cherries, apples, blackberries, and raspberries, provide additional nutrients and sugars.
Beyond nuts, seeds, and fruits, gray squirrels incorporate other plant parts into their diet, including tree buds, flowers, and bark. They also eat fungi, such as mushrooms and truffles. While their diet is predominantly plant-based, gray squirrels are omnivores and will occasionally consume animal matter. This can include insects, bird eggs, young birds, small invertebrates, or carrion when other food sources are scarce.
Opportunistic Feeding and Human Environments
Gray squirrels adapt their diet in human-dominated landscapes to include readily available human food sources. They frequently visit bird feeders, consuming items such as corn and sunflower seeds. Gardens can also become foraging grounds, with squirrels eating produce like tomatoes, corn, and squash. They may also scavenge discarded human food items from trash bins.
However, many human foods are unsuitable or harmful for squirrels. Processed foods, sugary items, and excessive bread offer little nutritional value and can lead to health issues. Bread, for instance, is low in fiber and can cause digestive problems or malnutrition. Salted nuts and other salty snacks are particularly detrimental, as squirrels cannot efficiently process large amounts of sodium, potentially leading to dehydration, kidney damage, or seizures. Foods containing chocolate, artificial sweeteners like xylitol, avocado skin or pits, onions, and garlic are toxic and should never be given to squirrels.
Dietary Adaptations and Seasonal Changes
Gray squirrels adapt their diet to changing food availability throughout the year, driven by specific nutritional needs. Fat and protein are essential for energy, especially for survival during colder months. To prepare for periods of scarcity, squirrels engage in scatter hoarding, burying individual nuts and seeds in numerous shallow caches during the autumn. They rely on their spatial memory and keen sense of smell to locate these buried treasures later.
Their diet shifts significantly with the seasons. In fall, when nuts and seeds are abundant, these form the primary food source. As winter progresses and other foods become scarce, squirrels rely heavily on their cached stores, supplemented by tree buds, bark, and pine cones. During spring, when fresh vegetation emerges, their diet includes new shoots, tree buds, and flowers. By summer, fruits, berries, and insects become more prominent in their diet, providing a fresh influx of nutrients.