The American Black Bear (Ursus americanus) is known for its highly adaptable and opportunistic omnivorous diet. While their natural foraging primarily involves grasses, berries, nuts, and insects, black bears readily consume human-related food sources when available, including agricultural crops. Black bears certainly eat corn, and in areas where forests and croplands intersect, cornfields can become a major seasonal component of their diet. This preference is rooted in a fundamental biological need that peaks in the late summer and fall, drawing the animals into agricultural areas.
Corn as a Preferred Forage Item
Black bears are highly efficient foragers, recognizing corn as a dense, reliable, and easily digestible food source. Bears prioritize items that offer the maximum nutritional return for the least effort, and corn fits this calculation perfectly, particularly during its developmental stage.
Bears prefer to forage on corn when the kernels are in the “milk stage” (mid-to-late summer). At this point, the kernels are soft, sweet, and contain a high percentage of digestible sugars, making them palatable and easy to process. As the corn matures and dries, the bears’ interest tends to decrease, though they may still consume mature kernels if other food sources are scarce.
When feeding, a bear causes distinct damage, leaving large, localized areas of broken or smashed stalks flattened to the ground. Unlike deer or raccoons, a black bear typically consumes the entire cob, underscoring its focus on maximizing caloric intake.
The Caloric Imperative: Why Corn is Highly Sought
The powerful drive for bears to seek out high-calorie foods like corn is explained by hyperphagia, a seasonal biological process. This period of excessive eating begins in late summer and continues through the fall as the bear prepares for winter denning. During hyperphagia, a black bear may forage for up to 20 hours a day, consuming at least 20,000 calories daily—ten times its normal intake—to build fat reserves.
Corn is attractive because it provides a concentrated source of carbohydrates, which the bear’s body rapidly converts into the fat necessary for survival during hibernation. This accumulated fat serves as the body’s fuel source, sustaining the bear through several months of dormancy when it does not eat, drink, or excrete waste. Without sufficient fat reserves, which can constitute up to 30% of their body weight by autumn, bears may not survive the winter.
The high energy density of corn provides a much more efficient caloric return compared to many natural foods. While corn is not the most calorie-dense food available, its abundance in agricultural landscapes makes it an easily accessible and substantial source of carbohydrates. This intense nutritional requirement for fat deposition motivates bears to seek out and consume corn.
Behavioral Context and Human Conflict
The biological need for hyperphagia compels black bears to take risks near human activity in search of concentrated food sources, leading directly to conflict. Bears access corn primarily through crop raiding in large agricultural fields. Fields isolated or surrounded by wooded areas are disproportionately affected by bear damage, as the cover provides protection and bears are reluctant to venture far into open expanses.
The conflict extends beyond commercial agriculture into residential areas. Bears are strongly attracted to corn used as feed for livestock or wildlife, such as corn-based feed found in deer feeders. Similarly, improperly stored pet food or garbage containing corn products draws bears into backyards and neighborhoods, leading to property damage and increased human-wildlife encounters.
The high caloric payoff from human-associated foods reinforces risk-taking behavior in bears, reducing their natural wariness of people. This learned behavior creates a cycle where bears return repeatedly to human-populated areas for easy meals. Effective management requires securing these high-calorie attractants to discourage bears from associating human habitats with readily available food.