DIPUS, the jerboa, in natural history, a genus of Mammalia, of the order Glires. Generic character : two front teeth in the upper and in the under jaw ; fore legs very short, hind legs very long ; clavicles in the skeleton; tail long and tufted at the tip. Shaw enumerates six species, and Gmelin ten.
D., sagitta, or the Egyptian jerboa of Pennant, is about the size of a rat, and • was known to the ancients by the name of the two-footed mouse. It is to be met with in various parts of Africa, and in the IV.
eastern provinces of Siberia. In its pos ture and movement it greatly.resembles a bird. It stands on its hind feet, and rarely applies its fore feet to the ground, em ploying them almost exclusively in apply ing food to its mouth, in the same manner as the kanguroo. It inhabits subterra neous apartments prepared by itself, or found accommodated for its purpose, and reposes in them during the greater part of the day, choosing the night for excur sion and food. It is, in the tropical cli mates, susceptible of cold, feeds upon various vegetables, such as it can procure amidst the barren and sandy wilds, which it prefers for its habitation, and burrows with such extreme facility, that, in a state of confinement, it will, in no long time, work a passage through a wall of brick. M. Sonnini considers the jerboa as constituting a link between quadru peds and birds. The beginning of the connection between the former and the latter is considered by Shaw as formed by the jerboa, and the last link as com pleted in the bat. In the sand and ruins about Alexandria the jerboa is very fre quently to he found. It is, however, ex tremeiy shy, retiring on the slightest alarm to its habitation, and the common mode of destroying them among the Arabs, as related by Sonnini, is by stop ping up all the accesses to their residence Out one, and watching their egress at that. In Egypt they are used as food. M. Sonnini kept several in a cage fbr a considerable time, feeding them on teal. nuts and other fruits. They appeared extremely fond of basking in the sun, and indeed, in the sunshine, were often extremely alert and playful. They were mild in their dispositions even in feeding, spewing no tendency to quarrelsomeness, or ferocity ; but, on the other hand, they exhibited little or no susceptibility of gra titude or attachment, df joy or fear, and their manners were characterised by a cold and stupid indifference. See Mam
malia, Plate IX. fig. 5.
D. Canadensis, is an inhabitant of North America, particularly the northern states. This is the smallest species of the jerboa, being about the size of a mouse. Gene ral Davies had several specimens in his possession, and his account of this curious animal is to be found in the fourth volume of the transactions of the Linnxan Socie ty. In company with several other gen. tlemen, the General caught one of these jerboas, in a large field, after an hour's chase, during which the little creature took the extraordinary leaps of from Three C. e to five yards in almost uninterrupted sue cession, sinking, however, at length, un der fatigue from such wonderful exer tions. Its food could not be ascertained by the General, who offered it a great variety, no article of which it appeared at all disposed to touch, and the day after its seizure it died, overwhelmed, proba bly, by its extreme efforts to escape from its pursuers. It is sometimes found dor mant, and in this ,state, probably, passes the winter in the rigorous climate of Ca nada. A specim8n of it in this state was brought to the General, after having been found by a labourer, whose spade struck against a substance, about the size of a cricket ball, which, on examination, was found to inclose a jerboa, completely rolled up, and in a state of torpor. The ball was found about a foot and a half un der the surface of the ground, was per fectly smooth internally, and about an inch in thickness. This case, which was composed of clay, was somewhat lated by the accidental blow of the work man, but was deposited by the General, with its contents, in his room, in a small box supplied with some cotton, in hopes that, as the warm season advanced, the animal would revive from its suspended vitality. This hope, however, was not gratified. As the jerboa is not seen in Canada from October till May, it may be concluded that it passes the winter in this curious envelope. See Mammalia, Plate IX. ,fig. 6.