Interactions
Living in such a wide stretch of
wilderness, you would think that a grizzly bear is solitary and
wouldn’t interact too often with other organisms. In fact, there
are key interactions that influence a grizzly bear. Most of
these interactions are one-sided with the grizzlies
out-competing the other organisms, except for the case with
humans. Rarely do any conflicts result in death by either
organism.
Black Bears
Black bears are the most common competitor with
grizzlies. They inhabit the same areas in the southern end of the grizzly
bear range, such as Yellowstone National Park, and have similar herbivorous
diets. Because black bears are generally smaller, they will either run or
climb a tree to avoid confrontation with grizzlies. Due to their large size
and greater need for resources, grizzlies out-compete black bears and can
drive them out of their territory.
Wolves
Competition between wolves and grizzlies has increased since the reintroduction of gray wolves to Yellowstone National Park in 1995 (Fortin et al. 2013). Most conflict occurs when a grizzly is scavenging for food and comes across wolves with their kill. The wolves may try to defend their kill if there are enough in the pack, or else they may leave it behind because it is not worth the risk to fight off a grizzly for minimal food.
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Squirrels
Squirrels are scavengers of nuts, and they store
their resources in their nests. Grizzlies are also scavengers and will eat
nuts if they are readily available. Grizzlies will sometimes scavenge
squirrel nests and eat the nuts that the squirrels have collected. If the
squirrels are hibernating, they may be eaten as well.
Humans
With the human population ever expanding, they are
crowding out the natural habitat of the grizzly bears through urbanization.
Places such as Yellowstone National Park have also become popular tourist
attractions causing a lot contact between the two, especially during summer
months: the peak time of tourism and grizzly bear activity.