THE BURROWING MAMMALS, AND OTHERS, No. 42.
North America is wonderfully rich in species of gnawing animals, and the end is not yet. The investigations of our mammalogists are adding new species with a degree of rapidity and parallelism that is fairly bewildering.
It is the duty of the Zoological Society to do its utmost to increase as much as possible the sum total of knowledge of our largest Order of Mammals. Manifestly, however, it is impracticable to do more than place before visitors a reasonable number of well-chosen types, which shall represent as many as possible of the twelve Families, and also the genera most worth knowing.
The most serious obstacle in the way of anyone who attempts to exhibit collections of living rodents lies in the natural propensity of so many species to keep out of sight during the daytime. This is particularly true of the members of the Mouse, Pocket Gopher, and Pouched Rat Families, comprising about three hundred species in all. With very few exceptions, the whole matter of the exhibition of collections of living rodents is something new, and every step is an experiment. In the belief that even the most shy burrowing animals will appreciate abundant room, perfectly natural surroundings, plenty of food, and immunity from annoyance, and eventually fall into the habit of spending many of the daylight hours above ground, as do prairie-dogs, the Society has constructed a series of fifteen small yards, each 10x20 feet, bounded by walls going down to bedrock, and enclosed above by a box-like arrangement of very light wire-netting 5 feet high. The ground is chiefly undisturbed soil of a firm and gravelly nature, thoroughly drained, and all earth filling has been tightly rammed into place to prevent caving in the burrows. Above ground, each yard contains weathered rocks, stumps, and hollow logs in abundance.
In these fifteen yards, each of which will hold specimens of at least two or three species, will be placed strongly marked types of those families whose representatives are most numerous in North America, and also the least known, only a few of which may be mentioned here.
The Sewellel Family, (_Aplodontidae_), contains five or six species and is of unusual scientific interest. The Sewellel, Mountain Beaver, Farmer or "Showt'l" (_Aplodontia rufus_ and _major_), is an animal of the size and general appearance of a large, short-tailed muskrat. It inhabits a few localities in remote regions in the mountain-valleys of northern California, Oregon, Washington, and southern British Columbia. It feeds like a beaver, climbs bushes four feet high, burrows in _wet_ ground, and fights like a little fiend when brought to bay. Notwithstanding the size of this animal, it is very seldom seen, and is but little known.