Muskoxs will even charge birds

The muskox, or its ancestor, is believed to have migrated to North America between 200,000 and 90,000 years ago. It is agreed however that the muskox was alive in the Pleistocene period making it a contemporary of the mammoth.		It is thought that the muskox was able to survive the last ice age (Wisconsin glaciation) by finding ice free areas away from prehistoric peoples. The muskox gradually moved across North America and arrived in Greenland during the late Holocene.
During the mating season, which peaks in mid-August, muskox males compete for dominance, and one dominant bull drives other adult males out of the group.		Non-breeding males will often form male only herds of 3-10 or wander the tundra alone. During this period all males are extremely aggressive.	During the mating season,all males are extremely aggressive. Bulls will even charge birds if they are close by.