Why are grizzly bears not successful predators for elk?

Grizzly bears are actually very successful predators of elk. In fact, elk are one of the grizzly bear's primary food sources. Grizzly bears are ambush predators and will often wait for elk to come close before attacking. They will also chase down elk if they have the opportunity. Grizzly bears are powerful animals and can easily kill an elk with a single blow from their paws or teeth.