Last updated 9 December 2000: corrected link to Caviomorpha page.
Rodents are the largest order of mammals in the world, comprising about 40% of the toal mammalian species. While this is still only just over half of the total species of lizards or snakes, and a fraction of the number of species of birds and insects, the number of species (about 1,500-2,000, depending on which book or source you take as authoritative) does not truly represent the diversity and sheer numbers of rodents on earth.
The order of rodents is divided up into three suborders or infraorders: the Sciuromorpha (squirrel-like rodents), the Myomorpha (mouse-like rodents) and Caviomorpha (cavy-like rodents). These groups are described in more detail below, but it can be generally noted that Myomorpha constitute the largest group of rodents by far (as might be expected!) and that Caviomorpha are mainly confined to South America.
Suborder Sciuromorpha (squirrel-like rodents)
Suborder Myomorpha (mouse-like rodents)
Suborder Caviomorpha (cavy-like rodents)