The white-footed mouse, scientifically known as Peromyscus leucopus, is one of North America’s most widespread and abundant small rodents. This adaptable mammal inhabits a vast range, stretching from southern Canada down to Mexico, thriving in deciduous forests, brushy areas, and agricultural fields. The species is classified as an omnivore, meaning its diet shifts based on the seasonal availability of resources within its habitat.
Primary Plant-Based Foods
The foundation of the white-footed mouse’s diet consists of high-calorie, starchy plant matter that provides dense energy for daily activity. Seeds from grasses and weeds form a consistent part of its foraging efforts, often supplemented by grains found in agricultural or disturbed areas. These small items are relatively easy to find and consume, forming a steady caloric intake during most months.
The most significant plant-based food source, particularly in wooded habitats, comes from mast crops, which are the fruits and nuts of forest trees. Acorns from oak trees, along with hickory nuts and beechnuts, are highly sought after due to their high fat and carbohydrate content. These mice are accomplished climbers, which allows them to access these resources directly from branches or to quickly gather them after they fall to the forest floor.
When available, softer plant materials like berries and small fruits are readily consumed, providing water and simple sugars. These items are typically consumed during the warmer months when they ripen, offering a temporary dietary boost. The mice will also sometimes consume parts of the plant structure itself, such as the bark, tender leaves, or flowers, though these are lower in overall nutritional value compared to seeds and nuts.
Essential Non-Plant Dietary Components
While plant matter supplies the bulk of their energy, the white-footed mouse requires other food types to meet its need for protein, fat, and minerals. Invertebrates are the most significant non-plant component, serving as a rich source of protein, especially during the spring and summer breeding seasons. They actively hunt and consume a variety of insects, including beetles, crickets, caterpillars, and spiders.
This insect consumption provides a valuable ecological service, as the mice are known to eat pest species, such as the larvae and pupae of the gypsy moth. Beyond insects, the mice will occasionally consume other animal matter, including bird eggs found in low nests or the flesh of small vertebrates if they encounter carrion. Fungi, such as mushrooms and truffles, are also a regular part of their diet, providing different nutrients and helping to disperse fungal spores throughout the ecosystem.
To maintain proper bone structure and physiological function, the mice will even gnaw on bone fragments or shed antlers they find on the ground. This behavior helps supplement their calcium and mineral intake, which can be lacking in a purely seed-based diet.
Food Storage and Seasonal Adaptations
The white-footed mouse does not hibernate, which necessitates a year-round strategy for maintaining its energy reserves, particularly in colder climates. Caching, the hoarding of food in numerous stashes located near their nests or throughout their home range, is essential. They utilize cheek pouches to transport multiple seeds or nuts at once, quickly depositing them in hidden spots like hollow logs, abandoned bird nests, or underground burrows.
The dietary focus shifts dramatically with the seasons; the summer and early autumn are periods of abundance, characterized by the consumption of fresh insects, berries, and newly ripened seeds. This allows them to build up fat reserves before the cold weather arrives. The winter diet, by contrast, relies almost entirely on the cached seeds and nuts gathered in the fall, supplemented only by occasional foraging for roots or bark beneath the snow.
They manage their energy expenditure during the harshest periods by entering daily torpor, a state where their body temperature and metabolic rate are temporarily lowered. This energy saving, combined with reliance on localized food caches, allows Peromyscus leucopus to remain active throughout the winter months.