Science and conservation for the world’s 2800 small mammal species


Hispaniolan hutia

Hispaniolan hutia Plagiodontia aedium

Without question, rodents are the world’s most successful group of mammals, and represent an important ecological component of virtually every terrestrial ecosystem. There are over 2200 living species, comprising around 40 percent of all of the mammal species existing today, and they have an almost worldwide distribution. Rodents are characterized by a single pair of continuously growing, gnawing incisors in their upper and lower jaws, which enable them to feed successfully on a huge range of different food types.

Over half of all rodents are classified within just two families of relatively small-bodied species – the Muridae (the largest mammal family, comprising true rats and mice, gerbils and relatives) and the Cricetidae (including hamsters, voles, lemmings and rice rats). However there are over 30 other living rodent families, containing species with a wide range of different ecologies and habits. From giant arboreal flying squirrels to blind subterranean naked mole rats, and from aquatic beavers to bipedal hopping kangaroo rats, giant jumping rats and springhares, rodents are truly diverse. New rodent species also continue to be discovered by researchers, and many of these newly described species – such as the highly unusual Sulawesi shrew-rat Paucidentomys vermidax, a specialized worm-eating animal with a long thin snout and no molars – reveal more and more about the extreme evolutionary diversity of this remarkable mammal group.


Click on the family names below to learn more about each one:

Suborder Anomaluromorpha

– Family Pedetidae

Suborder Castorimorpha

Superfamily Geomyoidea 

– Family Geomyidae

– Family Heteromyidae

Superfamily Castoroidea

– Family Castoridae

Suborder Hystricomorpha

Infraorder Ctenodactylomorphi 

– Family Cuniculidae

Infraorder Hystricognathi

– Family Bathyergidae

– Family Chinchillidae

– Family Ctenomyidae

– Family Thryonomyidae

Suborder Myomorpha

Superfamily Dipodoidea

– Family Zapodidae

Superfamily Muroidea

– Family Muridae

– Family Platacanthomyidae

– Family Spalacidae

Suborder Sciuromorpha

– Family Aplodontiidae