What do bears eat?

All  living things need to consume food to sustain life. For wild animals finding adequate food is a primary task. Nutritional needs vary with the seasons. Understanding seasonal dietary requirements and habits provides insight into bear behavior and lets people know how to be a good neighbor. This article is about the ‘O’s’ of the black bear diet.

Omnivore

Black bears are omnivorous, meaning they eat both plants and animals. These mammals are at the top of the food chain due to their large size, powerful bite, and speed. Yet, they do not indiscriminately kill and are far more likely to forage than kill. Grubs and mature insects such as ants, beetles, hornets, yellowjackets, and termites are favorites from the animal kingdom.

Ant larvae and pupae are called “brood.” These digestible clumps of fat and protein are good sources of animal protein for black bears that have long, sticky tongues for probing into ant colonies. It is a delicacy for young cubs eating their first solid foods. Bears find brood by keying in on pheromones and other chemicals ants use for communication and defense. They eat mainly the brood, not the adult ants which use offensive formic acid and citronella for defense. Bears usually avoid anthills because digging into them mixes too much soil with the brood. Instead, they tear into logs or flip over rocks and other cover to ingest clumps of brood with a few flicks of their sticky tongues.  And rood is a good source of protein in early spring while plants are still greening up.  Leaving downed logs for ant colonies and other insects directly contributes to food for black bears.

 But overall, black bears eat mostly plants, estimates are that between 70% to 95% of their diet is plant based.  Among the black bear’s favorite plant foods are acorns, nuts, roots, berries, leaves and twigs,  sedges and grasses, mushrooms,  dogwood,  and dandelions.  Black bears and other wildlife will benefit from as much native plant material as can be made available. Removing invasive plants (such as stilt grass) and making space where leaf litter or mulch is not suppressing all plant growth can help. Letting the dandelion and other ‘weeds’ grow in early spring is useful not only to the pollinators but to bears as well.

On the Move

Bears are kind of unique in that they cycle through available food sources. They take advantage of what is ripe at any given time of the year, and move from one source to the next, bingeing almost exclusively on a single source until it is exhausted. In the early spring, black bears target tender green shoots and weeds like dandelions before switching to ripe berries throughout the summer, then gorging themselves on hard mast like nuts in the fall. In an abundant habitat, their summer diet might start with blackberries before transitioning to wild cherries, then sassafras and pokeberries later on in the summer, then elderberries and persimmons.

As Bent Tree has worked with Amicoloa EMC  to not indiscriminately spray herbicides under power lines, blackberry has begun to return in these sunny areas. Volunteering with Lake & Wildlife to minimize young tree growth under the power lines will ensure this strategy continues and directly contributes to fruitful food sources for bear and other wildlife.

Opportunistic

Black bears are known to take advantage of an easy meal. If hungry, they will pretty much eat anything they comes across.  In the spring, black bears may prey on young deer fawns if they happen to find one.   They even occasionally hijack carcasses of animals that were killed by another predator.  Much conflict with humans is due to the bears opportunistic approach to food. If human food sources are readily available, a black bear will take advantage.  Feeding bears or allowing them access to human food, bird seed, and garbage causes a number of problems:

• It changes the bear's behavior and causes them to lose their instinctive fear of humans. Over time, these bears may begin approaching people in search of food and may become more unpredictable and dangerous.

• Bears that obtain human food and garbage damage property and injure people. These bears pose a risk to public safety. They can also teach other bears this dangerous behavior.

• Studies have shown that bears that lose their fear of people by obtaining human food and garbage never live as long as bears that feed on natural foods and are shy and afraid of people. Many are hit by cars and become easy targets for poachers.

Other, or Oh My Goodness – they tried to eat what? 

 Many human items have fragrant ingredients that attract bears, some that you’d not really think of them as food – like cosmetics and sunscreen and bug spray.  Bears will bite into insulated hot tub covers, and refrigerator walls because these items all produce formic acid when the formaldehyde in the insulation breaks down, making them smell like ant colonies.  Citronella products contain a compound that is attractive to bears, likely because they also smell like ant colonies.  While it may seem counterintuitive, wildlife repellents such as deer or rabbit repellents, can attract bears because of their smell.  Garden fertilizers and compost, particularly anything containing fish emulsion, is a prime attractant. The bear’s very keen sense of smell can lead them to gum wrappers left in a car, or soda residue in a glass on a porch.  

Given their broad dietary flexibility and adaptiveness to thrive in close proximity to humans, it can be a challenge to share habitat with black bears.  As Bent Tree residents we want to be safe and also enable the bears to live wild. This requires us to understand their motivation and diligently monitor and control our own causal behaviors.  We need to maintain their natural food sources and minimize enticements to our human food sources.