1911 Encyclopædia Britannica/Kangaroo-Rat

KANGAROO-RAT, a name applied in different parts of the world to two widely different groups of mammals. In Australia it is used to denote the small kangaroo-like marsupials technically known as Potoroinae, which zoologists prefer to call rat-kangaroos (see Marsupialia and Kangaroo). In North America it is employed for certain small jumping rat-like rodents nearly allied to the pocket-gophers and belonging to the family Geomyidae. Kangaroo-rats in this latter series are represented by three North American genera, of which Dipodomys phillipsi, Cricetodipus agilis and Microdipodops megacephalus may respectively be taken as examples. Resembling pocket-gophers in the possession of cheek-pouches, kangaroo-rats, together with pocket-mice, are distinguished by their elongated hind-limbs and tails, large eyes, well-developed ears and general jerboa-like appearance and habits. The upper incisor teeth are also relatively narrower, and there are important differences in the skull. The cheek-teeth are rootless in kangaroo-rats, but they develop roots in the pocket-mice. The former inhabit open, sandy districts, where they burrow beneath rocks or stones, and hop about like jerboas; their food consisting of grasses and other plants.