The chipmunk is a small, diurnal rodent recognized by the stripes along its back and sides. They are distributed across North America and Asia, inhabiting environments from forests to suburban yards. Chipmunks are classified as omnivores, consuming a diverse array of food sources. Their activity focuses on foraging during warmer months to secure energy for winter inactivity.
The Primary Foraged Plant Sources
The bulk of a chipmunk’s diet consists of plant materials, providing carbohydrates and fats for energy and storage. A significant portion of this intake is hard mast, which includes energy-dense nuts and seeds of woody plants. Examples include acorns, hickory nuts, beechnuts, and walnuts. Chipmunks harvest these items directly from trees or collect them from the forest floor.
They also rely on soft mast, which is perishable and includes wild fruits and berries like blackberries, wild cherries, and plums. Chipmunks consume seeds from grasses, flowers, and the winged seeds (samaras) of trees like red maple. They forage for subterranean and surface fungi, such as mushrooms and truffles, inadvertently helping disperse spores. Green vegetation, including young shoots and buds, is incorporated into their spring and summer diet for moisture and nutrients.
Protein Needs and Opportunistic Consumption
Although plant matter is the majority of their diet, chipmunks require protein, especially during growth and reproduction. They obtain this protein by actively hunting or opportunistically consuming small invertebrates. These animal sources provide concentrated nutrition difficult to acquire from plants alone.
Invertebrates consumed include:
- Caterpillars
- Grubs
- Worms
- Slugs
- Beetles
Chipmunks occasionally display predatory behavior, consuming bird eggs or nestlings encountered in low-lying nests. This opportunistic feeding extends to human-altered environments and non-native food sources. They frequently take sunflower seeds and cracked corn from bird feeders. They are also known to damage gardens by eating vegetables like corn and squash or digging up flower bulbs.
Caching Behavior and Winter Preparation
Chipmunks gather and store food using their expandable cheek pouches. These pouches allow them to carry multiple items, such as large nuts or dozens of small seeds, back to their burrow in a single trip. This efficient transport system helps build up winter stores quickly.
They employ a caching strategy called larder hoarding, concentrating a large supply of food in a dedicated chamber within the burrow system. This differs from scatter hoarding, which involves burying small, individual caches across a wide area. During winter, chipmunks enter a state of torpor rather than continuous hibernation, waking up periodically every few days. When they rouse, they access their stored larder, feed, and return to torpor, surviving the cold season without needing to forage above ground.