Again and again when he was filling his pouches from a pile of rolled oats in my hand I lowered it in a gently sloping position within ten or fifteen inches of another mouse gathering food on the ground. Thereupon the little bobtail in my hand would invariably leave the task of filling his pouches and without hesitation leap down on the back of the one on the ground. The surprised animal thus assailed from an unexpected quarter always fled in terror.
After a short pursuit the bobtailed one would come running back and instead of going to the equally inviting pile of food on the ground would come straight to my hand and complete his task. The industry of the little animals appeared to be tireless, as working swiftly they made trip after trip with pouchloads of food to their stores and quickly returned. One night I watched this strenuous work for two hours until I retired.
The abundance and boldness of pocket mice and kangaroo rats at this place led me to believe that there had been a former abundance of their food here, resulting in a large increase in the rodent population, but that it was then becoming scarce through a failure of rain to renew the seed harvest. The invariable outcome in such cases is for the small rodents dependent on seeds and fruits to be reduced by famine until they become rare, where previously they existed in great numbers. This is one of Nature’s processes whereby the danger of the overwhelming increase of any species is automatically prevented.
Photograph by Howard Taylor Middleton
YOUNG RED SQUIRRELS AND THEIR NEST
These cute little chaps were found cozily at rest in their nest in a pine. They were routed out, however, long enough to have their portraits taken. An effort was made to include the mother, but without success ([see page 556]).
THE POCKET GOPHERS (Geomys bursarius and its relatives)
(For illustration, [see page 515])
With the exception of the moles no other extensive group of American land mammals is so highly specialized for a peculiarly restricted mode of life as the pocket gophers. They form a strongly marked family, the Geomyidæ, which includes various genera and many species, all very similar in external form, but varying from the size of a large mouse to a massively formed animal equalling a large house rat in weight.