The northern grasshopper mouse (Onychomys leucogaster ) is a North American carnivorous rodent of the family Cricetidae. It ranges over much of the western part of the continent, from southern Saskatchewan and central Washington to Tamaulipas in northeast Mexico.
This grasshopper mouse can be found in prairies with low grass, dry areas, and also pasture lands of the central and southwestern parts of the United States. O. leucogaster has been known to associate positively with black-tailed prairie dogs, possibly due to their preference for disturbed areas, suitable habitat in the form of burrows, or food supply. The northern grasshopper mouse lives in burrows underground, by either digging its own or inhabiting burrows that have been disowned. These mice have a system of multiple burrows, with each burrow serving a different function. The nest burrow is the primary area of activity during the day; since they are nocturnal, they do not need to be in a burrow during the night. To keep moisture in during the day, they close up the opening. A retreat burrow serves for quick escape from predators. Its design is about 10 inches into the ground at a 45° angle. The cache burrow is used for storing seeds. The signpost burrows are small and filled with glandular secretions that mark the boundaries of their territory. All of these burrows are found within a large area of territory.
The northern grasshopper mouse has about two or three litters a year consisting of two to seven young, with the average being four. They have a gestation of 32–47 days, and the young are born in either late fall or early winter, between September and February. The male gathers and provides food for the female while she is pregnant and taking care of her young. The northern grasshopper mouse is an altricial species; baby mice are naked with closed eyes when they are born, and weigh about three grams. Both sexes reach their sexual maturity at three months, but the lifespan of a typical mouse living in the wild is only a few weeks to a few months.
