Bears are highly adaptable omnivores, consuming both plant and animal matter. For many species, ants are a regular and substantial part of their seasonal diet. This consumption of ants and their larvae, known as myrmecophagy, is a common behavior observed across several bear species globally. Bears routinely exploit sources of concentrated nutrients, relying on insect colonies as readily available packets of energy to supplement their foraging.
The Role of Insects in Bear Diets
Bears are generalists, constantly searching for the most calories for the least effort. Although plants like berries, roots, and grasses form the majority of their annual intake, insects represent a rewarding, high-calorie animal protein source that is relatively easy to catch. Insectivory is favored during the late spring and early summer when fruits and nuts are not yet abundant. Bears systematically seek out and exploit accessible insect sources, including beetle larvae, bees’ nests, and colonies of ants and termites. This helps bears maintain weight and replenish reserves when other food sources are temporarily scarce.
Bear Species That Consume Ants
The reliance on ants varies significantly across the eight species of the Ursidae family, reflecting differences in habitat and specialization. The American Black Bear (Ursus americanus) frequently consumes ants and termites throughout its range, often making ant brood a major source of animal protein from late spring into mid-summer. In some northern regions, ant consumption can account for over half of the bear’s diet volume during peak insect season. The Sloth Bear (Melursus ursinus), native to the Indian subcontinent, is the most specialized ant-eater among the bears. These bears have evolved specific physical features, including a long lower lip and a gap in the front teeth, to facilitate vacuuming up termites and ants. Brown Bears, or Grizzlies (Ursus arctos), are opportunistic feeders, consuming ants when nests are encountered but relying less heavily on them than black bears. The Sun Bear (Helarctos malayanus) also includes ants, termites, and bee larvae in its omnivorous diet.
Hunting and Consumption Techniques
A bear’s keen sense of smell is the initial tool used to locate ant nests, which are often concealed underground, beneath rocks, or inside decaying logs. Bears key in on the pheromones and chemical signals the ants use for communication and defense. Once a colony is located, the bear uses its physical strength and long claws to tear open the protective structure. For nests inside logs or under rocks, the bear rapidly strips away the wood or flips the stone to expose the inner chambers. The speed of consumption is necessary, allowing the bear to ingest the nutrient-rich contents before the adult ants can mount a defense. Bears use their long, sticky tongues to quickly lick up the brood and adult ants. The Sloth Bear has a specialized method, using its claws to open a termite or ant mound and then sucking up the insects with a loud, distinct vacuuming sound. While consuming the ants, the bear is exposed to formic acid, the defensive chemical sprayed by certain ant species. The bear tolerates this irritation, as the caloric reward outweighs the temporary discomfort.
Nutritional Motivation for Ant Consumption
The primary incentive for foraging is the larval and pupal stages, collectively called the ant brood, rather than the adult insects. The brood represents a digestible and concentrated source of fat and protein. Adult ants are less desirable due to their hard exoskeletons and the formic acid they release for defense. The seasonal timing of ant consumption aligns with the presence of the brood, peaking in late spring and early summer. This protein and fat surge is beneficial for bears emerging from hibernation, as they need to replenish protein reserves lost over the winter. Furthermore, the ant brood is an important source of high-quality nutrients for lactating females and rapidly growing cubs. The energy payoff of ant harvesting is significant, especially when berries or nut crops fail, forcing bears to rely more heavily on these insect sources to build up the necessary fat reserves for the coming winter.