The common perception of a squirrel is that of a harmless, bushy-tailed rodent focused solely on burying nuts and foraging for seeds. This image overlooks a surprising aspect of their diet and behavior. Squirrels absolutely will consume a lizard, a behavior that often shocks those who view them only as herbivores. This action is not a regular habit but an opportunistic feeding response driven by specific nutritional requirements that nuts and seeds alone cannot always provide.
Squirrels: Defining the Omnivore
Squirrels are classified as omnivores, meaning their diet naturally includes both plant and animal matter, though the bulk of their food intake is typically plant-based. While they are well-known for consuming fungi, seeds, nuts, fruits, and tree buds, their digestive system is also capable of processing meat. This capacity for animal consumption means squirrels are highly adaptable and resourceful survivors.
To supplement their main diet, squirrels regularly consume a variety of non-plant items. These animal sources include insects, bird eggs, and even nestlings or small birds. Flying squirrels, in particular, have been noted to have a more carnivorous diet compared to their tree-dwelling cousins. This range of food demonstrates a fundamental biological capability to utilize animal protein when the opportunity arises.
The Specific Case of Lizards
Lizard consumption is a documented observation across various species, including the eastern gray and red squirrels. Scientific studies have confirmed that lizards and other small vertebrates are occasionally part of their diet. This predatory behavior is considered facultative, meaning the squirrel can switch between eating plants and hunting animals based on resource availability.
Successful predation on a fast-moving animal like a lizard relies heavily on opportunity. Squirrels are not skilled hunters, so they tend to target vulnerable prey, such as a slow, injured, or young lizard. Ground squirrels are often observed preying more frequently than tree squirrels, likely due to their closer proximity to accessible ground-dwelling prey. Once caught, the lizard is consumed entirely, reinforcing that this is a true feeding event.
Dietary Drivers: The Need for Protein and Calcium
The biological necessity behind this opportunistic predation is the concentrated nutritional value found in animal matter. Lizards provide an excellent source of protein and, significantly, calcium, which are often scarce in a purely seed-and-nut diet. Nuts and seeds are high in phosphorus but low in calcium, creating a poor calcium-to-phosphorus ratio that can lead to health issues like Metabolic Bone Disease (MBD).
The demand for these concentrated nutrients is particularly high for females that are pregnant or lactating. Raising young requires a substantial intake of protein and calcium for proper development and bone strength. When natural sources of calcium like shed antlers or insects are unavailable, a lizard becomes a highly valuable, high-density food source to meet these physiological needs. This behavior is a matter of survival and nutritional balance, highlighting the squirrel’s role as an opportunistic survivor.