Large and in charge
Grizzly bears are Yellowstone’s biggest carnivores, making them formidable competition for wolves. They are 1-2 times larger than the more common black bears and are more aggressive. Grizzlies eat what wolves eat (and much more) and they are very successful at taking carcasses from wolves. However, as wolves generally retreat, is uncommon for grizzlies and wolves to kill each other.
Grizzlies hibernate in the winter. Mother bears give birth to up to four cubs in the winter den, then care for those cubs for about two years. Mother bears protect their cubs ferociously so wise animals give them a wide berth.