Several types of kangaroos have evolved, each living in a slightly different environment. Gray kangaroos are smaller than other varieties and dwell in open woodlands, most commonly on the southern reaches of the continent of Garund. Giant kangaroos, found primarily on the dry steppes of northern Casmaron, grow to twice the size of standard kangaroos, and the thunderous noise of their passing can be heard and felt from miles away. The kangaroo family also has several smaller relatives, including wallabies and pademelons. Some kangaroos exist in captivity in other parts of the world, but attempts to introduce them into other regions have-so far-largely failed.