Water mouse can refer to several types of not closely related semiaquatic rodents of superfamily Muroidea: Chibchanomys, two cricetid species from western South America; Las Cajas water mouse (C. orcesi) Chibchan water mouse (C. trichotis) Ethiopian water mouse or Ethiopian amphibious rat (Nilopegamys plumbeus), a murid; Rheomys, four cricetid species from Central America and Mexico; Mexican water mouse (R. mexicanus) Goldman's water mouse (R. raptor) Thomas's water mouse (R. thomasi) Underwood's water mouse (R. underwoodi) Xeromys myoides, a rodent native to Australia and Papua New Guinea