The western deermouse or western deer mouse (''Peromyscus sonoriensis'') is a

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

native to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It is widespread throughout the western half of the continent, mainly in areas west of the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

Taxonomy

It was formerly confused with the eastern deermouse (''P. maniculatus''), with both species being grouped under ''P. maniculatus'' as the North American deermouse. However, due to the significant morphological variation in the species, there was always long-standing confusion over the actual taxonomy of ''P. maniculatus''. A 2019 study found significant genetic divergence within the species and split it into two, with ''maniculatus'' representing the "eastern" group and ''sonoriensis'' representing the "western" group.

Description

''P. sonoriensis'' is covered in soft fur that ranges from gray to brown, but all of a distinctive white underside and white feet. As with their close relative, ''P. maniculatus'', they have many subspecies, including a distinctive "forest" and "grassland" morph. The "forest" morph has a long tail, large ears, and long hind feet, and inhabits western

boreal forest Taiga (; rus, тайга́, p=tɐjˈɡa; relates to Mongolic and Turkic languages), generally referred to in North America as a boreal forest or snow forest, is a biome characterized by coniferous forests consisting mostly of pines, spruces, ...

as well as coastal forests of the western

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. The "grassland" morph has short tails, small ears, and small feet, and inhabits the prairies and grasslands of the continental interior and extends into the deserts of the

American Southwest The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

Distribution and habitat

''Peromyscus sonoriensis'' is an abundant species in areas of

west of the

. They are populous in the western mountains and live in wooded areas and areas that were previously wooded. Deer mice inhabit a wide variety of plant communities including grasslands, brushy areas, woodlands, and forests.Whitaker, John O., Jr. (1980). ''National Audubon Society field guide to North American mammals.'' New York: Alfred A. Knopf, Inc. In a survey of small mammals on 29 sites in subalpine forests in

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

and

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

, the deer mouse had the highest frequency of occurrence; however, it was not always the most abundant small mammal.Raphael, Martin G. (1987). Nongame wildlife research in subalpine forests of the central Rocky Mountains. In: Management of subalpine forests: building on 50 years of research: Proceedings of a technical conference; 1987 July 6–9; Silver Creek, CO. Gen. Tech. Rep. RM-149. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 113–122 Deer mice were trapped in four of six forest communities in eastern

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

and northern

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

, and they were the only rodent in

ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...

(''Pinus ponderosa'') savanna. Although found throughout most of western North America, it is absent from parts of the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, Ne ...

and most of

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, where it is instead replaced with the similar

southern deer mouse The southern deermouse or southern deer mouse (''Peromyscus labecula'') is a species of rodent in the family Cricetidae. It is found in the United States and Mexico. Taxonomy The species was originally thought to be conspecific with the North ...

(''P. labecula'') and black-eared mouse (''P. melanotis''),

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

and most of

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

south of

San Francisco Bay San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland. San Francisco Bay drains water from a ...

, where it is replaced by

Gambel's deer mouse Gambel's deermouse or Gambel's deer mouse (''Peromyscus gambelii'') is a species of rodent in the family Cricetidae. It is native to the United States and Mexico. Taxonomy It was formerly considered a subspecies of the western deer mouse (''P. ...

(''P. gambelii''), the coastal region of the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...

from Washington northwards, where it is replaced by the

northwestern deer mouse The northwestern deer mouse or Keen's mouse (''Peromyscus keeni'') is a species of rodent in the family Cricetidae. It is found in British Columbia in Canada and in Alaska and Washington in the United States. It was named after the Rev. John Hen ...

(''P. keeni''), and

Yukon Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, where it is replaced by the

Yukon deer mouse The Yukon deermouse or Yukon deer mouse (''Peromyscus arcticus'') is a species of rodent in the family Cricetidae. It is endemic to Yukon Territory in Canada. Taxonomy The species was first identified as ''Peromyscus arcticus'' in 1845 by Joha ...

(''P. arcticus'').

Reproduction and life span

The species is polygynous, meaning that one male mates with multiple females.

Breeding season

Plumas County, California Plumas County () is a county in the Sierra Nevada of the U.S. state of California. As of the 2020 census, the population was 19,790. The county seat is Quincy, and the only incorporated city is Portola. The largest community in the county is ...

, deer mice bred through December in good mast (both soft and hard masts) years but ceased breeding in June of a poor mast year.Baker, Rollin H. (1968). "Habitats and distribution". In: King, John Arthur, ed. ''Biology of Peromyscus (Rodentia)''. Special Publication No. 2. Stillwater, OK: ''The American Society of Mammalogists'' 98–126. Deer mice breed throughout the year in the

Willamette Valley The Willamette Valley ( ) is a long valley in Oregon, in the Pacific Northwest region of the United States. The Willamette River flows the entire length of the valley and is surrounded by mountains on three sides: the Cascade Range to the east, ...

, but in other areas on the

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

coast there is usually a lull during the wettest and coldest weather.Maser, Chris; Mate, Bruce R.; Franklin, Jerry F.; Dyrness, C. T. (1981). Natural history of Oregon Coast mammals. Gen. Tech. Rep. PNW-133. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. In southeastern

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

at least one-third of captured deer mice were in breeding condition in winter.

Longetivity and mortality

O'Farrell reported that a population of deer mice in

big sagebrush ''Artemisia tridentata'', commonly called big sagebrush,MacKay, Pam (2013), ''Mojave Desert Wildflowers'', 2nd ed., , p. 264. Great Basin sagebrush or (locally) simply sagebrush, is an aromatic shrub from the family Asteraceae, which grows in ari ...

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

s had completely turned over (e.g., there were no surviving adults of the initial population) over the course of one summer.

Predators

Deer mice are important prey for snakes (Viperidae), owls (Strigidae), minks (''

Neovison vison The American mink (''Neogale vison'') is a semiaquatic species of mustelid native to North America, though human intervention has expanded its range to many parts of Europe, Asia and South America. Because of range expansion, the American mink ...

''), martens (''

Martes americana The American marten (''Martes americana''), also known as the American pine marten, is a species of North American mammal, a member of the family Mustelidae. The species is sometimes referred to as simply the pine marten. The name "pine marten" ...

'') and other mustelids, as well as skunks ('' Mephitis'' and ''

Spilogale The genus ''Spilogale'' includes all skunks commonly known as spotted skunks. Currently, there are four accepted extant species: ''S. gracilis'', ''S. putorius'', ''S. pygmaea'', and ''S. angustifrons''. New research, however, proposes that ther ...

'' spp.),

bobcat The bobcat (''Lynx rufus''), also known as the red lynx, is a medium-sized cat native to North America. It ranges from southern Canada through most of the contiguous United States to Oaxaca in Mexico. It is listed as Least Concern on the IUC ...

s (''Lynx rufus''),

domestic cats The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of t ...

(''Felis catus''),

coyote The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...

s (''Canis latrans''), foxes (''Vulpes'' and ''Urocyon'' spp.), and ringtail cats (''

Bassariscus astutus The ringtail (''Bassariscus astutus'') is a mammal of the raccoon family native to arid regions of North America. It is widely distributed and well adapted to disturbed areas. It has been legally trapped for its fur. It is listed as Least Conc ...

''). They are also parasitized by ''

Cuterebra fontinella ''Cuterebra fontinella'', the mouse bot fly, is a species of New World skin bot fly in the family Oestridae. ''C. fontinella'' is typically around in length with a black and yellow color pattern. ''C. fontinella'' develops by parasitizing nutrien ...

''.

References

{{Taxonbar, from=Q107404806 Peromyscus Rodents of North America Mammals of Canada Mammals of Mexico Mammals of the United States Mammals described in 1845 Taxa named by Johann Andreas Wagner