Jumping Mouse
2 of the 6 encyclopedias on this shelf carry an entry for Jumping Mouse. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a North American rodent related, not very closely, to true mice. The entire family consists of a single species confined to North America . The body of the adult is about three inches long. The tail is five inches long. The hind legs are very long; the forelegs, short. The hind foot is over one-third as long as the body. The hips are large, the fore parts short. Hips, rear legs, feet, and tail are adapted for taking long leaps. In some ways the jumping mouse reminds the observer of the smallest species of kangaroo found in Australia, but the American animal is entirely without the pouches for the young. The fur is coarse, and is of an intense yellowish cast, with pencilings of brownish black, due to long hairs on the back. The under parts are white. The following account is from the pen of Mr. Slade in Merriam's Mammals of the Adirondacks: The long-tailed jumping mouse inhabits high land or low land, forest or pasture, cultivated field or swamp, and appears to be equally at home in either, and numerous in any situation. It possesses a momentary agility second to no other rodent, and a muscular strength of enormous power for so small a creature. When suddenly disturbed, it often moves away in a direct line, the first three or four leaps being eight or ten feet in length; but these distances rapidly decline to about four feet, which are continued until it considers itself out of danger. This is not always the case for it frequently takes an irregular course and jumps at diverse angles for several successive leaps. . . . It feeds upon the buds, leaves, and twigs of many kinds of plants, upon seeds, grain, wild berries, chestnuts, acorns, grass, and, to some extent, upon the bark of shrubs. . . . As a rule, three litters are produced in a season, each consisting of from two to four young.
Collier's New Encyclopedia (1921)
found in Labrador and North America generally, but especially an inhabitant of the fur territories. Like the jumping hare, it is classified by some with the jerboas, and is one of the smallest of these forms.
What Has Changed in the Last Century
Aiton's stated in 1910 that "the entire family consists of a single species confined to North America" — that has not held. Zoologists now recognize several North American jumping mice, including the woodland jumping mouse (Napaeozapus insignis) and the western Zapus princeps, and they are grouped with the Old World birch mice in the family Zapodidae, within the same superfamily as the jerboas — so Collier's 1921 hint that "it is classified by some with the jerboas" was closer to the modern arrangement. Neither account mentions the trait that most defines the animal today: it is one of the few true hibernators among American rodents, spending six months or more underground in a torpid coil. Two forms have since become conservation causes rather than curiosities — the Preble's meadow jumping mouse was listed as threatened under the US Endangered Species Act in 1998, touching off years of dispute over whether it was a valid subspecies, and the New Mexico meadow jumping mouse was listed as endangered in 2014.
Written for this edition, 2026.