Plains Harvest Mice are found in grassy areas, including hay and wheat fields. They seem to prefer shorter grasses, and build round nests of grass on or near the ground. Newborns are blind and hairless, and weigh about a gram, but are weaned at about two weeks and are adult-size in five weeks.

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