|Northern Grasshopper Mouse
Onychomys leucogaster (Wied-Neuwied)
Description: Northern grasshopper mice can be distinguished from other members of the family by: 1) thick body, 2) short tapering tail less than one-half the length of head and body, the terminal third of which is white while the rest is white below and brownish above, 3) soft, silky pelage which varies in color with age, the upperparts being buffy to reddish-brown (rarely black), sometimes slightly darker on the middle of the back in young adults, and light gray in older individuals, 4) white underparts, feet and basal ear tufts, 5) dark patch on the front upper edge of the ear, and 6) eyes surrounded by dark skin. Immatures are lighter than young adults and range in color from pale grayish to grayish-brown. Sexes are alike.
Size: Adults may attain the following dimensions: total length 135-160 mm; tail 37-51 mm; hind foot 20-24 mm; ear 14-19 mm; weight 30-50 grams.
Range and Habitat: Northern grasshopper mice inhabit dry, sandy, or loose soil in open grasslands and shrublands. Individuals in western Kansas tend to be lighter in color than those from eastern Kansas. High densities have been recorded in cornfields (Fleharty and Choate, 1986).
Reproduction: Northern grasshopper mice breed mostly from spring to early fall (April to September). After a gestation period averaging 30 (with a range of 26 to 35) days, two to six (usually four) young are born hairless with eyes and ears closed. At seven days their ears open and some teeth erupt. They are furred in eight to twelve days; their eyes open in 12-16 days. In 24 days, when half grown, they are weaned. Sexual maturity is reached in three to four months.
Habits: Northern grasshopper mice are uncommon in Kansas. They are strictly nocturnal and spend considerable time underground in abandoned burrows of other mammals where they rest during the day. A pair will also construct their own U-shaped nest burrow and rear their young together. Although these mice remain active year round, they remain in their nest during severe weather and at low temperatures. Mated pairs are intolerant of other grasshopper mice, and vocal signals may serve to space the population. "Sandbathing" is another characteristic activity, and "dust wallows," which may also serve as "scent posts," are found around the perimeter of a grasshopper mouse territory. Northern grasshopper mice are highly vocal and give a variety of barking sounds, as well as a high-pitched "howl".
Food: This mouse is more carnivorous than other mice and consumes up to 90 percent animal material. As the name implies, they eat great numbers of grasshoppers as well as other invertebrates, but they are also active predators of other small rodents, which they stalk, grasp with their long claws, and kill with a bite of their long, sharp incisors at the base of the prey's neck. Water is acquired from eating animal tissue.
Remarks: Northern grasshopper mice are preyed upon by owls, foxes, coyotes, bobcats, snakes, and other small predators. Longevity of this small mammal is up to three years.
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