How many species of rats exist? - briefly
Approximately 60 distinct rat species are recognized globally. They are classified mainly within the genus Rattus and a few closely related genera of the Muridae family.
How many species of rats exist? - in detail
The genus Rattus comprises the true rats. Current taxonomic consensus recognizes roughly 70 distinct species within this genus, although estimates vary between 60 and 80 depending on the authority consulted. Species are grouped into several subgenera that reflect geographic and morphological differences.
Key groups include:
- Australasian clade – species such as Rattus fuscipes (bush rat) and Rattus lutreolus (Australian swamp rat) inhabit New Guinea, Australia, and surrounding islands.
- Asian‑Pacific clade – contains Rattus exulans (Pacific rat) and Rattus rattus (black rat), both widespread through islands of the Indian and Pacific Oceans.
- Eurasian clade – features Rattus norvegicus (brown rat) and Rattus tanezumi (Asian house rat), species that have achieved a global distribution via human activity.
Beyond the Rattus genus, additional rodent species are colloquially called “rats” but belong to other genera, such as the African giant pouched rat (Cricetomys gambianus) and the marsh rice rat (Oryzomys palustris). Including these, the total count of rat‑like rodents exceeds 100 species.
Taxonomic revisions continue to refine species boundaries, especially in regions with high biodiversity like Southeast Asia and the Pacific. Molecular analyses frequently reveal cryptic lineages, suggesting that the actual number of distinct rat species may increase as new data become available.