How many rat species exist on Earth? - briefly
Approximately 64 distinct species are classified within the genus Rattus, the group most commonly identified as true rats. When broader murid rodents colloquially termed rats are included, the worldwide count approaches 200 species.
How many rat species exist on Earth? - in detail
Rats belong to the family Muridae, subfamily Murinae, and are classified within the genus Rattus and several related genera. Current taxonomic surveys recognize approximately 70 distinct rat species worldwide, with Rattus norvegicus (the brown rat) and Rattus rattus (the black rat) comprising the majority of human‑associated populations.
Key points about global rat diversity:
- Genus Rattus – around 60 species, distributed across Asia, Africa, Oceania, and the Americas.
- Related genera – species such as Berylmys, Bandicota, Niviventer, and Tarsomys are often colloquially called rats; these add roughly 10 additional species to the total count.
- Geographic hotspots – Southeast Asia hosts the highest concentration, with many endemics confined to specific islands or mountain ranges.
- Habitat range – species occupy forests, grasslands, wetlands, arid zones, and urban environments; some are strictly arboreal, others are ground‑dwelling.
- Conservation status – most rat species are listed as Least Concern, but several island endemics are classified as Vulnerable or Endangered due to habitat loss and invasive predators.
Taxonomic revisions based on molecular phylogenetics continue to refine species boundaries, occasionally splitting previously lumped taxa or synonymizing others. Consequently, the exact number may adjust as new data emerge, but the consensus figure remains close to seventy recognized species across the world.