Beavers are significantly less active in cold weather. With plenty of stored food and the security of a strong dam, they can conserve their energy from late fall to early spring. Beaver dens are the key to their winter survival. Though they rarely leave their lodges once the temperatures drop, beavers do not hibernate. However, they do prepare carefully for the colder months. Beavers gather vegetation to store in underwater caches, so they can eat without needing to forage throughout the winter.