Many species of mice eat insects or meat and even on occasion devour one of their own kind. The grasshopper mice go far beyond this and are often not only as fierce flesh eaters as real carnivores, but make their diet, at least during the summer season, mainly of insects and other small invertebrates. Their bill of fare includes a miscellaneous assortment of several species of mice, including their own kind caught in traps, small dead birds, lizards, frogs, cutworms, scorpions, mole crickets, ordinary crickets, grasshoppers, moths, flies, and beetles, including the “potato bug.” In addition they eat many kinds of seeds, fruit, and other vegetable matter. Where obtainable, grasshoppers are one of their favorite foods, and from this they receive their common name. In Colorado, from their fondness for scorpions, they are sometimes called “scorpion mice.” Vernon Bailey’s observations of a grasshopper mouse he had in captivity are illuminating as to their habits, and indicate that their presence in numbers about cultivated land must be of distinct economic value. When undisturbed and well fed the captive was entirely nocturnal, sleeping all day and becoming very active at night. While usually quiet, sometimes jumping with all his force he tried furiously to escape from his small prison box. His favorite food consisted of crickets, grasshoppers ranking next. Among other things he ate were a black beetle, ladybirds, a potato beetle, spiders, bugs, and dragon flies. In feeding he sat upright on his haunches and held the insects in his front paws, eating them head first. Large grasshoppers, their tails resting on the ground, were held head up by a paw on each shoulder. A grasshopper would sometimes kick so vigorously as to tip the mouse off its balance, but was never relinquished until decapitated. The mouse promptly killed and ate a small frog placed in his box and was expert at catching flies. He ate many kinds of insects, including a live wasp, but appeared terror-stricken if a few ants were put in with him. When a dozen or more crickets and grasshoppers were put into his box at the same time he at once proceeded to bite off all their heads before beginning to feast upon them. A dead white-footed mouse was dropped in and “he pounced upon it like a cat, caught it by the side of the head near the ear, and began biting it with all the ferocity of a coon dog.” The bones could be heard cracking and after the little beast appeared satisfied that his prey was really dead he ceased worrying it and an examination showed that he had bitten through its skull deep into the brain. Afterward he tore off and ate fragments of flesh from its head, neck, and shoulders. The ferocious certainty with which he seized the white-footed mouse by the head and bit through its skull indicated that in relation to small mammals he, probably like all his kind, had the predatory instincts and habits of the carnivores.