Transactions of the Linnean Society of London/Volume 4/An account of the jumping mouse of Canada. Dipus canadensis
|Transactions of the Linnean Society of London, Volume 4 (1798)
An Account of the Jumping Mouse of Canada. Dipus Canadensis by Thomas Davies
X. An Account of the Jumping Mouse of Canada. Dipus Canadensis.
By Major General Thomas Davies, F.R.S. and L.S.
Read June 6, 1797.
AS I conceive there are very few persons, however conversant with Natural History, who may have seen or known there was an animal existing in the coldest parts of Canada, of the same genus with the Jerboa, hitherto confined to the warmer climates of Europe and Africa; I take the liberty of laying before this Society the following observations (accompanied by a drawing) on an animal of that kind, procured by myself in the neighbourhood of Quebec, during my last residence in that country. As I do not recollect to have seen this animal either figured or described by any author in Natural History, I flatter myself, these observations may afford some satisfaction to the President and Members of the Linnaean Society. The specimens from which I made the drawing are now in my collection. With respect to the food, or mode of feeding of this animal, I have it not in my power to speak with any degree of certainty, as I could by no means procure any kind of sustenance that I could induce it to eat; therefore, when caught, it only lived a day and a half. The first I was so fortunate to catch was taken in a large field near the Falls of Montmorenci, and by its having strayed too far from the skirts of the wood, allowed myself, with the assistance of three other gentlemen, to surround it, and after an hour's hard chase to get it unhurt, though not before it was thoroughly fatigued, which might in a great measure accelerate its death. During the time the animal remained in its usual vigour, its agility was incredible for so small a creature. It always took progressive leaps of from three to four, and sometimes of five yards, although seldom above 12 or 14 inches from the surface of the grass; but I have frequently observed others in shrubby places and in the woods, amongst plants, where they chiefly reside, leap considerably higher. When found in such places, it is impossible to take them, from their wonderful agility, and their evading all pursuit by bounding into the thickest cover they can find.
With respect to the figure given of it in its dormant state, I have to observe, that specimen was found by some workmen, in digging the foundation for a summer-house, in a gentleman's garden about two miles from Quebec, in the latter end of May 1787. It was discovered enclosed in a ball of clay, about the size of a cricket-ball, nearly an inch in thickness, perfectly smooth within, and about 20 inches under ground. The man who first discovered it, not knowing what it was, struck the ball with his spade, by which means it was broken to pieces, or the ball also would have been presented to me. The drawing will perfectly shew how the animal is laid during its dormant state. How long it had been under ground it is impossible to say; but as I never could observe these animals in any parts of the country after the beginning of September, I conceive they lay themselves up some time in that month, or beginning of October, when the frost becomes sharp; nor did I ever see them again before the last week in May, or beginning of June. From their being enveloped in balls of clay, without any appearance of food, I conceive they sleep during the winter, and remain for that term without sustenance. As soon as I conveyed this specimen to my house, I deposited it, as it was, in a small chip-box, in some cotton, waiting with great anxiety for its waking; but that not taking place at the season they generally appear, I kept it until I found it begin to smell: I then stuffed it, and preserved it in its torpid position. I am led to believe its not recovering from that state arose from the heat of my room during the time it was in the box, a fire having been constantly burning in the stove, and which in all probability was too great for respiration. I am led to this conception from my experience of the Snow Bird of that country, which always expires in a few days (after being caught, although it feeds perfectly well) if exposed to the heat of a room with a fire or stove; but being nourished with snow, and kept in a cold room or passage, will live to the middle of summer.
The animal above described belongs to Schreber's genus of Dipus, and may be characterised
palmis tetradactlylis, plantis pentadactylis, cauda annulata undique setofa corpore longiore.
Tab. viii. Fig. 5. represents the Dipus canadensis, of its natural size, in an erect position.
Fig. 6. shews it in a torpid state.