Do grizzly bears eat musk oxen?

Grizzly bears have been observed preying upon the calves of Musk ox, particularly when conditions are poor and it has difficulty in securing its preferred foods; and is known to kill adult Musk ox calves on very rare occasions in the wild when they are very hungry from a very lean season, or the Musk ox is injured or sick from starvation, or during the birthing period from stress and exhaustion when they are at their weakest when vulnerable to being attacked and eaten for food..