It has a thick coat, and was common in the northern hemisphere during the Pleistocene ice age. The males give off a strong odour, hence its name. This musky odour is used to attract females during mating season. Musk oxen travel in herds of females and their young led by one or two strong males. Male oxen fight over who will be leader by butting their thick heads and horns against each other. The musk oxen's long, curved horns keep away predators. When a herd smells nearby wolves, all the musk oxen form a circle and face out. They lower their heads to show off their horns.