The Collaborative International Dictionary
kangaroo rat \kangaroo rat\ n. (Zool.) A jumping rodent of the genus Dipodomys of the family Heteromyidae, which lives in arid regions of Mexico and the western U. S.
2. (Zool.) An Australian mammal of the genus Notomys.
3. (Zool.) a small ratlike Australian kangaroo of the genus Potorous, also called the potoroo.
Potoroo \Po`to*roo"\, n. (Zo["o]l.) Any small kangaroo belonging to Hypsiprymnus, Bettongia, and allied genera, native of Australia and Tasmania. Called also kangaroo rat.
Wiktionary
n. Any of many different species in genus ''Dipodomys'', rodents that move about by hopping.
WordNet
n. any of various leaping rodents of desert regions of North America and Mexico; largest members of the family Heteromyidae [syn: desert rat, Dipodomys phillipsii]
any of several rabbit-sized rat-like Australian kangaroos [syn: rat kangaroo]
Wikipedia
Kangaroo rats, small rodents of genus Dipodomys, are native to western North America. The common name derives from their bipedal form. They hop in a manner similar to the much larger kangaroo, but developed this mode of locomotion independently, like several other clades of rodents (e.g. dipodids and hopping mice).
Usage examples of "kangaroo rat".
A few hard pellets marked the droppings of a small rodent, perhaps a kangaroo rat.
The kangaroo rat is so aware of such sound that even on the darkest of nights it can hear the approaching slither of a hunting rattlesnake.
A kangaroo rat, collecting seeds in the dried grass near the glass doors, looks up curiously as Rachel leads Johnson down the steps.
A large running bird with yellow tail feathers appeared and scooped up a careless mammal that resembled a kangaroo rat.
Her capture noose whipped and snapped and threatened to unbalance her, yet she saw the wiry thief hop in circles like a kangaroo rat at the bottom of the slope.
Of course I do: it was as broad and populous a group as mammals, and even in a ghost town where there aren't any people, you'd expect to see a kangaroo rat or a prairie dog.