A reeler-phenotype neuronal mutant rat.

Callistomys pictus, a spiny rat from Brazil.

The aquatic larva of a hoverfly in either the tribe Eristalini or the tribe Sericomyini, which breathes through a tail-like air tube.

plural of rat-tailed maggot

A kind of rat with no thymus and thus a severely compromised immune system, used in medical research.

An outbred rat used in medical research, white with a black or brown hood.

Oryzomys couesi, a semiaquatic rodent in the family Cricetidae occurring from southernmost Texas through Mexico and Central America into northwestern Colombia.

(simile, informal) Soaked to the point of being highly unattractive; bedraggled.

(simile, slang, vulgar) Thoroughly crazy.

plural of rat-tat-tat