Deer are adaptable herbivores, consuming diverse plant matter to meet nutritional needs. Their diet changes significantly based on environmental availability throughout the year. This flexibility allows them to thrive across various landscapes.
Primary Components of a Deer’s Diet
A deer’s diet is primarily composed of various plant types, each contributing different nutrients. Browse, which includes the leaves, twigs, and young shoots of woody plants like trees and shrubs, forms a substantial part of their intake, often making up around 46% of their annual diet. This food source is consistently available and provides fiber and some minerals, becoming particularly important during colder months when other options are scarce.
Forbs are broad-leafed herbaceous plants, encompassing wildflowers and weeds, and are a highly digestible and protein-rich food source. These plants are especially sought after in late spring and summer, contributing significantly to a deer’s nutritional requirements during periods of growth and reproduction.
Mast, consisting of nuts and fruits, offers concentrated energy. Hard mast, such as acorns and hickory nuts, is rich in fats and carbohydrates, while soft mast, like berries and apples, provides sugars and vitamins.
Deer consume some grasses, particularly young shoots, when higher-quality forage is limited. They may also eat fungi and lichens. Agricultural crops like corn, soybeans, and small grains are readily utilized when accessible. Deer are selective feeders, choosing plants that best meet their nutritional demands for protein, energy, and minerals like calcium and phosphorus.
Seasonal Adaptations in Deer Feeding
A deer’s dietary choices shift with the seasons, adapting to the availability of forage and their changing physiological demands. During spring and summer, deer favor lush, green growth, consuming high-protein forbs and tender new browse. This nutrient-dense diet supports antler development in bucks, lactation in does, and the rapid growth of fawns.
As autumn arrives, deer transition their diet to focus on high-energy foods, primarily mast like acorns and other nuts. This shift helps them accumulate fat reserves essential for surviving the breeding season and the approaching winter months. Agricultural crops also become an important energy source during this period, if available.
Winter presents a challenging period for deer, with scarce food resources. Their diet relies heavily on woody browse, including twigs and dormant vegetation. To conserve energy, deer undergo metabolic adaptations, reducing their metabolic rate. Their digestive system also adjusts to process more fibrous, lower-quality forage, relying on microbial changes in their rumen to extract nutrients. Even with these adaptations, deer commonly experience weight loss.
What Not to Feed Deer
Feeding deer human-provided foods can cause harm. Deer possess a specialized digestive system that relies on a balanced microbial community to break down their natural diet. Introducing foods like bread, corn, or pet food can disrupt this balance, leading to digestive issues such as acidosis, diarrhea, and dehydration. Their digestive microbes require weeks to adapt to new food sources, making sudden dietary changes dangerous.
Artificial feeding alters natural deer behavior, causing them to congregate in high numbers. This increased density facilitates the spread of diseases, including Chronic Wasting Disease (CWD), tuberculosis, and parasites, posing threats to deer populations. Dependency on human handouts can also diminish their natural foraging instincts and migratory patterns.
Feeding deer can lead to safety concerns for both humans and animals. Deer accustomed to human presence may lose their natural wariness, becoming aggressive, especially during breeding season or when does protect fawns. Concentrated areas also increase the risk of deer-vehicle collisions as animals frequent populated areas. Feeding wild deer is illegal in many areas, often carrying fines.