Animals exhibit specific physical and behavioral adaptations which increase their chances of survival. For example, lions live in family units called prides. The pride is an important community that provides its members with food, protection, and territory. Lions are the only big cats that live in social groups. Other big cats live solitary lives, except when breeding or raising cubs. A lion pride may include up to three males, a dozen females, and their young. All of a pride's female lionesses and cubs are typically related. Young males leave the pride when they are two or three years old and attempt to take over another male's pride. The social structure of the pride is based on specific roles. Lionesses are the primary hunters, while dominant males are responsible for protecting the pride's territory. Lions are fierce predators that often stalk their prey before attacking. Their attacks cause their prey to panic and disperse. Then the lions can isolate and attack a weaker or slower individual. Lion prey includes antelopes, zebras, wildebeest, buffalo, and other grassland animals. These animals are often larger and faster than an individual lion. By hunting together, lions are able to exhaust and kill their prey. Sometimes lions scavenge or steal from other predators like cheetahs or hyenas.