How Many Species Of Kangaroo And Wallaby Are There?

　　The two families that make up the kangaroos and wallabies include about 60 species of marsupials. Together, their natural ranges extend through most of Australia, Tasmania, New Guinea and some nearby islands. Some species are very large, while others are the size of rats. They all have small heads compared to their total body size and, while their forelimbs are poorly developed (except in tree kangaroos), their hindlimbs are very powerful and are built for hopping.

　　The forelimbs are not used for locomotion - the hindlimbs provide all the power the animals need in order to move about. The large hindfeet have two enlarged toes with long claws. Two of the remaining toes are bound in a common sheath, with only their claws separated.

　　Because of its shape and adaptations, a kangaroo's body looks out of proportion, with the back half being so large and powerful in comparison to the front. The front of the body has to be light to give the correct weight distribution for efficient hopping.

There are 61 total species in the wallaby family:

The Banded Hare-Wallaby, 2 other hare-wallabies, 12 tree-kangaroos, 7
standard wallabies, 2 wallaroos, 4 kangaroos, 6 dorcopsis wallabies, 2
nail-tail-wallabies, 7 pademelon wallabies, 16 rock-wallabies, the
Quokka, and the Swamp Wallaby.

It seems to me strange that there are 60 species of kangaroo and wallaby,yet there are only about thirty species of wallaby,and five or six species of kangaroo! Perhaps 30 plus 6 adds up to sixty but I really don't see how. Is it 36 or 60? Please give me a straight answer!