Contrary to the common image of a bushy-tailed rodent solely focused on nuts, the truth about the squirrel diet is far more complex. An omnivore is an animal whose natural diet includes both plant and animal matter, and squirrels, by this definition, are indeed omnivorous. Their adaptability and resourcefulness in finding food sources beyond seeds and fruits truly define their classification. This realization shifts the perception of squirrels from simple herbivores to flexible foragers with a diverse menu.
Defining the Squirrel Diet
The bulk of a squirrel’s daily intake is composed of plant material, which is the diet most people are familiar with. Their foraging activities are heavily centered on collecting and consuming energy-rich items like nuts, seeds, and acorns. Squirrels also readily consume various fruits, berries, and fungi, including mushrooms and truffles, which provide vitamins, proteins, and minerals.
Seasonal availability dictates much of their diet, with tree buds, flowers, and tree bark often supplementing their meals, especially when nuts are scarce. While these plant-based foods form the foundation of their nutrition, they do not provide a complete nutritional profile for the animal.
The Evidence of Omnivory
Specific instances of consuming non-plant foods confirm the squirrel’s omnivorous nature. They are opportunistic eaters, meaning they will take advantage of easy-to-obtain animal protein sources. The most common animal matter consumed includes various insects, such as grasshoppers, beetle larvae, and caterpillars.
More surprisingly, squirrels are known to raid the nests of small birds. They will consume the eggs and even the defenseless nestlings, which represent a dense source of protein. Occasionally, squirrels will also prey on small vertebrates like mice, lizards, or small snakes, or scavenge on carrion. These predatory and scavenging behaviors, while not a daily occurrence, demonstrate a crucial dietary flexibility.
Why Squirrels Need More Than Nuts
The driver behind this opportunistic omnivory is the need to supplement a diet that is nutritionally incomplete. Nuts and seeds, while high in fat and energy, are notably low in certain minerals and protein. This is particularly problematic for calcium, which is required for bone health and proper metabolic function.
The need for calcium is dramatically increased during critical life stages, such as pregnancy and lactation. This is why pregnant and nursing female squirrels are more frequently observed seeking out animal-based foods. To compensate for the low calcium content in their typical diet, squirrels will gnaw on bones, shed antlers, and even turtle shells. This behavior, known as osteophagy, is a direct response to a nutritional deficit.