Muskoxen live in herds of 12–24 in the winter and 8–20 in the summer. They do not hold territories, but they do mark their trails with preorbital glands. Male and female muskoxen both have separate age-based hierarchies, with mature oxen being dominant over juveniles. Dominant oxen tend to get access to the best resources and will displace subordinates from patches of grass during the winter. Muskox bulls assert their dominance in many different ways. One is a "rush and butt", in which a dominant bull rushes a subordinate from the side with its horns, and will warn the subordinate so it can have a chance to get away. Bulls will also roar, swing their heads, and paw the ground. Dominant bulls sometimes treat subordinate bulls like cows. A dominant bull will casually kick a subordinate with its foreleg, something they do to cows during mating. Dominant bulls will also mock copulate subordinates and sniff their genitals. A subordinate bull can change his status by charging a dominant bull.