Merriam's Mesquite Mouse - Illustration by Bill Singleton

Merriam's Mesquite Mouse
Peromyscus merriami


Merriam's mesquite mouse is a pale-gray mouse with cream-colored underparts. It measures five and a half to six inches long with the tail included.1 The tail is bi-colored and makes up more than half the length of the mouse.1

Habitat: The mesquite mouse was once common in mesquite forests called bosques.2 It has also been found in dense brush in the low desert, associated with mesquite.3

Range: The mesquite mouse occupies Pinal, Pima, and Santa Cruz counties, Arizona, and areas farther south into Mexico.

Diet: The mouse feeds on mesquite pods and other seeds when available.2

Reproduction: Not much is known about the breeding habits of this mouse. Wild-caught mice have been observed to be pregnant at various times during the year. It is assumed that from the age of four months and for the next two years, a female mesquite mouse can have one litter per month.3

Status: The mesquite mouse is a Wildlife Species of Concern in Arizona.

Merriam's Mesquite Mouse in Pima County: The mesquite mouse has a small range in Pima County. The mouse has been found in areas of Organ Pipe National Monument, Sabino Canyon, Arivaca, Baboquivari Mountains, San Xavier and Fort Lowell.3 The mouse depends on mesquite bosques for food and shelter. Mesquite bosques are declining due to increased water use, grazing, and harvesting the wood for fuel use. According to Donald Hoffmeister, author of Mammals of Arizona, "the fate of mesquite mice in Arizona is precarious."


1. Whitaker, John O. 1986. The Audubon Society Field Guide to North American Mammals. New York: Random House. 467 pp.

2. Burt, William Henry. 1976. A Field Guide to the Mammals. Houghton Mifflin Company, Boston. pp. 162.

3. Hoffmeister, Donald. 1986. Mammals of Arizona. University of Arizona Press: Arizona Game and Fish.

back to Priority Vulnerable Species Fact Sheets