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.