Losea Rat

The Losea rat, also called the lesser ricefield rat, is a true rat in the Rattus rattus species group. It was originally described from Taiwan and has documented morphological, chromosomal and geographic differences from other regional Rattus. Modern genetic work separates the Thai species Rattus sakeratensis, which older references treated as part of R. losea (Mammal Species of the World; NCBI Taxonomy).

Its confirmed range includes Taiwan, southern China, Vietnam, central and southern Laos, south-western Cambodia and Thailand north of the peninsula. Because historical Thai records may include the now-distinct little Indochinese field rat, habitat and biological claims from older literature are not transferred here without specimen-level confirmation (Mammal Species of the World; molecular systematic study). It is Nationally Least Concern (Thailand Red Data 2025).