A male kangaroo is called a buck. Other nicknames for a male kangaroo are boomer, jack and old man. Male kangaroos can be distinguished from female kangaroos by the lack of a pouch on the stomach. They are also larger and slower than females.
A group of kangaroos is called a mob, a court or a troop. Fights between males can occur suddenly during grazing, or they can begin with both males scratching and grooming each other. Males attempt to push each other off balance and win the fight by pushing the opponent backwards or to the ground. Males form consort pairs with females and move on to another female after mating.