Smithsonian National Museum of Natural History, North American Mammals
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Reithrodontomys megalotis

Western Harvest Mouse

Order: Rodentia
Family: Cricetidae

Image of Reithrodontomys megalotis
Click to enlarge. (60 kb)

Conservation Status: Least Concern.

Western Harvest Mouse are adaptable, widespread, and abundant, especially in meadows, prairies, old pastures, stream valleys, and marshes. They eat seeds, insects, and plants. They rarely live for more than a year, but under optimal conditions, a female can produce more than 50 young in her lifetime. Their nests are built of plant material, usually on the ground, but sometimes in burrows or in vegetation slightly above the ground. Each mouse may have several nests, which it uses at different times. The Mice are nonterritorial and show a great deal of tolerance for one another, even huddling together when it is cold. Such intimate contact carries risks: they are afflicted with many parasites, including protozoans, worms, fleas, chiggers, mites, and lice. They are a vector for a hantavirus that can cause acute respiratory illness and hemorrhagic fever in humans.

Also known as:
Long-tailed Harvest Mouse, Desert Harvest Mouse, Dusky Harvest Mouse

Sexual Dimorphism:

Average: 140 mm
Range: 118-170 mm

Range: 8-15 g


Baird, S.F., 1857 [1858].  Mammals. In Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean, p. 451.  Vol. 8, Pt. 1. Mammals. Beverly Tucker Printer, Washington, D.C., 8(1):1-757.


Mammal Species of the World

Mammalian Species, American Society of Mammalogists' species account

Distribution of Reithrodontomys megalotis

Bones and Teeth

Reithrodontomys megalotis
First left lower molar, with right side toward front of the mouth. Click to enlarge. (19kb)

Reithrodontomys megalotis
First right upper molar, with right side toward front of the mouth. Click to enlarge. (18kb)