Kangaroos are the world's largest marsupials and the largest species of macropod. Large males can exceed 1.8 m when standing fully erect and reach a body weight of 90 kg. Adult females are always much smaller in size, reaching body weights of 30 - 40 kg.
Kangaroos are shy herbivores, active at dawn and dusk.
They are bipedal which means that they hop on their hind legs at speeds of up to 48 kilometres per hour for several kilometres and at 20 kph over very long distances. Grey and red kangaroos hop in characteristically different ways. The grey hops with a more vertical body axis while red kangaroos hop with a more horizontal body axis. Both species have a long tail which acts as a counterbalance when hopping and a prop when grazing. Kangaroos are gregarious, living in small family groups with the adult female the matriarch, and other group members females and young, usually related to her.