During the winter, they rely on bark and lichen. They forage mainly in the trees but will go to the ground to eat grasses and wild onions. In the winter, they break up into bands of 60-70, rarely fewer than 40. In the spring and throughout summer, bands may combine to form huge groups of 100-600. Males without females form bachelor groups.
Males fight to lead a harem , b ut it is the females that initiate mating.
Males and females have different calls. Group members may sing together in a chorus, and in captivity, mated pairs also sing together. Males twice as big and heavy at 16-35kg. One young, occasionally twins. Gestation about 200 days.