The New World genus Sylvilagus includes the many species of cottontail rabbit, which resemble the European rabbit in appearance, as well as the marsh rabbit and swamp rabbit ( Sylvilagus palustris and S. aquaticus, respectively), of the S United States. These rabbits do not burrow, although in winter they may shelter in a burrow abandoned by another animal. They usually rest, like hares, in hollows which they make in the ground or in vegetation. The Idaho pygmy rabbit, Brachylagus idahoensis, of the U.S. Great Basin, digs simple burrows. The many North American species called jackrabbit are actually hares, as is the snowshoe rabbit, or varying hare. There are several species of short-eared rabbits in Asia and one, the volcano rabbit, or Mexican pygmy rabbit ( Romerolagus diazi ), in central Mexico, where it is in danger of extinction.