Lions are the only cats that live in social groups, called prides. All of a pride's females are related and female cubs typically stay with the group as they grow up. Young male cubs will leave the group once they are mature to start their own pride. Males and females take on different roles in the pride. Male lions spend their time guarding their territory and their cubs. They maintain the boundaries of their territory by roaring, marking it with urine, and chasing off intruders. Their thick manes, a unique trait to male lions, protect their necks when they fight.