The kangaroo's family name, Macropodidae, means "big feet," a great description for kangaroos and their relatives. Confused about the difference between kangaroos, wallaroos, and wallabies? That's understandable! There are more than 50 species of these marsupials, and they vary in size from critters you could hold in your hands to the giant red kangaroo that stands as tall as an adult person. The main difference between a kangaroo and all the others is size: the six largest macropods are referred to as kangaroos. Otherwise, they are quite similar. Red-necked wallabies are mainly nocturnal and mostly solitary, but they will gather together when there is an abundance of resources such as food, water, and shelter.