BIO 203


The grizzly bear has adapted to better live in its environment. Below are some of the more useful adaptations that play a major role in the bear’s survival.


Because of the large size of the bears and the colder climate of their habitats, grizzlies must eat a lot of food to survive. The proportion of animals in the diet is positively correlated with latitude (Vulla et al. 2009), which says that the further north the bears are found, the more meat they consume.


To contribute to the omnivorous diet, the teeth of the grizzly bear must be able to tear apart meat and grind nuts and other vegetation. The American grizzly bear is decidedly more carnivorous than previously thought, thus routinely subjecting its canines to the predation of large prey (Christiansen 2008). Often the prey will be killed by mauling from the claws and not the teeth.


The claws of a grizzly bear are used for self defense and for collecting food. When subduing large prey, bears usually attack rather indiscriminately with both forepaws and teeth (Christiansen 2008). Bears will also dig into the ground or into tree trunks to scavenge for food.

Hibernation and Sleep Cycle

Due to long winters in the arctic climate creating a scarcity of food, grizzly bears will hibernate for four to six months, conserving energy until spring. During this time a bear will live off of its stored fat and will reduce its metabolic rate, and they tolerate extremely low heart rates without ventricular chamber dilation (Nelson and Robbins 2010).

During the rest of the year, grizzlies spend a lot of their time foraging for food. Due to the seasonal selection of foods, grizzlies adapt their diets and will require temporal flexibility (Fortin et al. 2013), meaning they will switch between diurnal and nocturnal activity patterns depending on when their foods are available.

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