White-tailed deer are herbivores, leisurely grazing on most available plant foods. Their stomachs allow them to digest a varied diet, including leaves, twigs, fruits and nuts, grass, corn, alfalfa, and even lichens and other fungi. Occasionally venturing out in the daylight hours, white-tailed deer are primarily nocturnal or crepuscular, browsing mainly at dawn and dusk.

Although previously depleted by unrestricted hunting in the United States, strict game-management measures have helped restore the white-tailed deer population.