Do bears really hibernate?
Hibernation is defined as a state of inactivity and metabolic depression in animals and is characterized by lower breathing rate, decreased body temperature, and/ or decreased metabolic rate. Hibernation conserves energy when food is in short supply during the winter months. With this definition, black bears can be considered as hibernators, since they undergo hibernation from December to the beginning of April. Bears in warmer areas may not hibernate at all depending on food availability.
Will black bears attack if you come near their dens?
Black bears generally avoid human contact and will not attack if you come near their dens, but they will defend themselves if you try to enter their dens. Other types of bears, such as brown bears, will attack if you approach their dens.
What do black bears eat?
The American black bear is both a generalist (eats a wide variety of foods) and an omnivore (eats both plants and meat). Black bears' diets are as varied as the different habitats in which they live. In Minnesota, after leaving their dens, bears seek out emergent spring vegetation such as horsetail, sedge, and aspen buds. As these spring plants become less nutritious in late spring, they tend to eat ants. Ants (and ant pupae) are abundant and provide a source that is high in protein. Rarely, bears in Minnesota will also utilize other high-protein sources of food, such as deer fawns. During the height of summer, bears hone in on berry species as they become ripe. Bears in Minnesota eat everything from raspberries to wild plums. In the fall, bears need to consume calorie-rich diets to prepare for hibernation; this time of intense feeding is known as hyperphagia. Typical fall foods include hazelnuts and acorns, while some bears living in close proximity to agriculture will supplement their diets with corn, oats, and sunflowers.
Are bears social animals?
Minnesota black bears are not typically social animals, however, females will stay with their cubs for a year and develop strong family bonds. They will also adopt cubs and yearlings that have been orphaned. Large gatherings of bears are also found around abundent food sources such as a salmon stream.
How is bear research conducted?
Black bears are able to emerge from hibernation very quickly and maintain most of their muscle mass over the wintering months. Because of this, adult bears and yearlings must be anesthetized before removing them from their dens for research. Bears are given anesthetic by one of two methods: 1) jab pole- the syringe is attached to a stick or tent pole and administered into the musculature of the bear; 2) dart gun- darts containing the anesthetic are shot from afar. Once the bears are weighed and the physiological parameters are obtained, the bears are placed back in their dens.
Above: Syringes contain an anesthetic and will be used in a dart gun.