At night, especially early in the evening, grasshopper mice utter a fine shrill whistling call note. This habit appears peculiar to them among all the mice and may be likened to that of many of the large beasts of prey in uttering their hunting call as they sally forth for the night’s foray.
THE WHITE-FOOTED MOUSE (Peromyscus leucopus and its relatives)
(For illustration, [see page 530])
Few of our smaller wild mammals are so generally known as the white-footed mice. Usually a little larger and proportionately shorter bodied than the house mice, they may at once be distinguished from them by the contrast between the delicate shades of fawn color, brown, or gray of the upper parts of the body, and the snowy white feet and under parts. Like other members of the genus, they have cheek pouches inside the mouth for gathering and carrying food to their stores.
Their exceedingly quick and graceful movements and their beauty of form and color would make them generally attractive were it not for the prejudice against all their kind resulting from the offensive ways of the house mouse.
Mice of the genus Peromyscus, to which the white-footed mice belong, are peculiar to North and South America and include more species and geographic races than any other American genus of mammals. The white-footed mice are limited to North America. Readily responsive to the influences of environment, they have developed numerous species and a large number of geographic races.
These are spread over most of the continent from the northern limit of trees to the tropical shores of Yucatan. One form has the distinction of living up to an altitude of from 15,000 to 16,000 feet on Mount Orizaba, Mexico, where I found its tracks in the volcanic ashes at the extreme limit of vegetation. This is the highest record for any North American mammal.
White-footed mice are active throughout the year and thrive in every variety of situation. In winter from the Northern States to the Arctic circle the snowshoer traversing the forest will note their lace-work patterns of tiny tracks leading across the snow from log to log or tree to tree. At sunrise on the southwestern deserts their tracks made during the night often form a fine network in the dust, but disappear with the first breath of the morning breeze.
They not only live everywhere in the wilderness, but are prompt to swarm about camps and other habitations, where they make free with the food supplies. Few frequenters of forest camps in the Northern States and Canada have failed to see the bright eyes of these pretty little animals peering at them from some crevice, or the mice scurrying along the log wall like little squirrels.
