(derogatory) Somebody deemed too reliant on welfare.

A dark rat once endemic to Christmas Island, Rattus nativitatis, now extinct.

Rattus macleari, a brown rat once endemic to Christmas Island, now extinct.

Alternative spelling of gym-rat

A species of rat found in southwestern Africa, Petromus typicus.

Any of the four species of burrowing rodents in the spalacid tribe Rhizomyini, found in China and southeast Asia

plural of rat run

Any of various groove-toothed rats of the genus Otomys, found in sub-Saharan Africa.

plural of rat flood

(India) A large invasion of black rats caused by the flowering of the bamboo Melocanna baccifera every 48 years in parts of India.