How many rat species exist? - briefly
Approximately 70 recognized species belong to the genus Rattus, the true rats, and they are found on every continent except Antarctica. These species vary in size, habitat preference, and geographic range.
How many rat species exist? - in detail
Rats belong primarily to the genus Rattus, which contains the majority of recognized species. Current taxonomic databases list between 60 and 70 valid species in this genus, with Rattus norvegicus (the brown rat) and Rattus rattus (the black rat) being the most widely distributed. The exact count varies slightly among authorities because of ongoing revisions, cryptic species discoveries, and synonymizations.
Beyond Rattus, numerous other muroid rodents are commonly called rats. These include:
- Bandicoot rats (Bandicota spp.): three species found in South and Southeast Asia.
- African giant pouched rats (Cricetomys spp.): two species inhabiting sub‑Saharan Africa.
- Polynesian rats (Uromys and Papagomys spp.): several species restricted to Pacific islands.
- Bush rats (Rattus spp. in Australia) and native New Guinean rats (Rattus and Papagomys spp.): several endemic forms.
When all rat‑like taxa are considered, the total number of species commonly referred to as rats exceeds 100. The majority are concentrated in tropical and subtropical regions, where habitat specialization drives diversification. Conservation status varies: some species are abundant and invasive, while others are threatened by habitat loss and limited ranges.
In summary, the genus Rattus comprises roughly 60–70 species, and the broader group of rodents identified as rats adds another few dozen, resulting in a global count of more than one hundred distinct species.