Deer are primarily plant-eating animals, with their biology and typical diet centered around vegetation. However, deer behavior can involve the surprising consumption of meat. This challenges the conventional understanding of these animals and raises questions about their dietary flexibility.
Deer as Herbivores
Deer are ruminant herbivores, primarily consuming plant matter. Their diet includes leafy parts of woody plants, broad-leaved plants, fruits, seeds, and grasses. Their digestive system, featuring a four-chambered stomach (rumen, reticulum, omasum, and abomasum), is adapted to ferment plant material and extract nutrients. Unlike grazers, deer are selective browsers, preferring digestible shoots, young leaves, and fruits.
Instances of Deer Consuming Meat
Documented instances show deer consuming meat despite their herbivorous nature. They scavenge on animal carcasses like roadkill or other remains. Deer have been recorded gnawing on bones, a behavior often captured by trail cameras. These observations include them consuming dead squirrels, fish, and even human remains at forensic research facilities.
Beyond scavenging, deer engage in more active carnivorous behaviors. They have been observed preying on small animals, such as bird chicks or rodents. While not typical, these instances highlight an opportunistic aspect of deer feeding habits, showing their diet can extend beyond plants when opportunities arise.
Why Deer Might Eat Meat
Deer consume meat due to nutritional deficiencies. Their plant-based diet can sometimes lack specific minerals like calcium and phosphorus. These minerals are important for antler growth in males and for milk production and fetal development in females. When scarce in plants, deer may seek them from animal remains, such as bones.
Opportunistic feeding also occurs during extreme hunger or when conventional food sources are limited. Harsh winters, for instance, can reduce palatable plant forage. In such conditions, deer may consume any readily available food source for necessary nutrients, even animal matter. This behavior is a response to biological need.
Potential Risks of Carnivorous Deer Behavior
Consuming meat carries risks for deer, mainly disease transmission. A concern is the spread of prion diseases like Chronic Wasting Disease (CWD), which affects deer, elk, and moose. CWD prions are resilient and persist in the environment. If a deer consumes tissues from an infected animal, it could contract the disease.
No confirmed human cases of CWD have been reported, but it is a theoretical risk, especially for those consuming venison from infected animals. Studies in monkeys suggest CWD can transmit through infected brain or meat tissues. Reports link CWD-infected deer meat to human prion diseases, though experts research a definitive causal link.