Deer are widely perceived as peaceful herbivores, gracefully foraging on plants in forests and meadows. This understanding is largely accurate, as they are primary consumers in many ecosystems. However, their diet holds a surprising flexibility, occasionally encompassing more unusual food sources beyond typical plant matter. This adaptability is rooted in their survival instincts and nutritional requirements.
Primary Diet of Deer
Deer primarily consume a diverse range of plant-based foods. They are classified as both browsers and grazers, adapting their diet based on seasonal availability and their specific habitat. Their digestive system, a four-chambered stomach, is designed to break down fibrous plant materials efficiently.
Their diet includes leafy parts of woody plants like twigs, buds, and leaves from shrubs and trees. Forbs, broad-leaved herbaceous plants like wildflowers and legumes, also form a significant portion of their intake. Additionally, deer consume fruits, berries, nuts, and mushrooms, especially in the fall when these high-energy foods become abundant. An adult deer may consume between 7 to 15 pounds of diverse plant material daily, depending on the season and food availability.
Rare Dietary Deviations
While primarily herbivorous, deer occasionally consume animal matter, a behavior driven by specific environmental pressures or nutritional needs. This includes carrion, small birds, and even afterbirth. For example, deer have been observed eating dead fish along lake shores and depredating the nests of northern bobwhites.
Regarding rabbits, deer do not actively hunt or kill them. Their teeth are not suited for tearing flesh, making it impossible to hunt and consume live prey like rabbits. However, if a deer encounters a dead rabbit carcass, particularly during periods of food scarcity like harsh winters, it may scavenge and consume parts of it, such as ears and legs. This opportunistic feeding behavior has also been observed with other small animals like squirrels and birds, especially nestlings.
Deer also consume their own placenta after giving birth. This behavior helps to remove any scent that might attract predators to the vulnerable newborn fawns and provides the doe with rich nutrition to aid in her recovery and support milk production. These rare instances of consuming animal protein are not indicative of a shift to a carnivorous diet but rather highlight a survival mechanism.
Broader Context of Opportunistic Foraging
The occasional consumption of animal matter by deer exemplifies opportunistic foraging. This behavior is usually triggered when their primary plant-based diet cannot supply sufficient amounts of certain nutrients. For instance, periods of nutritional deficiency, such as during harsh winters when plant availability is low, can lead deer to seek alternative food sources.
Minerals like calcium and phosphorus are particularly important for deer, especially for bucks during antler growth and for does during pregnancy and lactation. If these minerals are scarce in their plant diet, deer may gnaw on bones or consume carrion to obtain them. Protein deficiency can also prompt this behavior, as meat provides a concentrated source of protein and energy. While deer’s digestive systems are primarily adapted for plants, they can process small amounts of meat, and such consumption can provide a temporary boost of these essential nutrients. This dietary flexibility demonstrates how survival instincts can lead animals to deviate from their typical feeding patterns when their specific nutritional needs are unmet.