The fulvous Harvest Mouse is a nocturnal species that lives in grassy fields where there are shrubs. These Mice are good climbers, and build baseball-sized nests up off the ground, in vegetation. Winter nests are sturdier than summer nests. When a nest is occupied—often by two Mice—the one or two entrances are plugged. Fulvous Harvest Mice eat invertebrates when they are available, during the spring and summer, and switch to seeds in fall and winter. Along the Texas coast, where invertebrates are available year-round, they are the dominant item in the diet. Males and females seem to travel together, which suggests they may pair-bond in monogamous relationships, a rarity for mammals. These Mice live for about a year, and seldom longer than 14 months.

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account