The cactus mouse (''Peromyscus eremicus'') is a species of

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 ...

in the family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and has m ...

. It is a species of the genus ''

Peromyscus ''Peromyscus'' is a genus of rodents. They are commonly referred to as deer mice or deermice, not to be confused with the chevrotain or "mouse deer". They are New World mice only distantly related to the common house and laboratory mouse, ''Mu ...

'', a closely related group of New World mice often called "deermice" (although the term more commonly refers specifically to '' P. maniculatus''). They are native to desert areas of southwestern

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 ...

Description

Cactus mice are small

cricetid The Cricetidae are a family (biology), family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, Muskrat, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest Fa ...

rodents, with large eyes and ears, a pointed snout, and a long monocolor tail. Avarage dimensions for ''P. eremicus'' are as follows: total length, 160mm to 211mm; length of body, 72mm to 100mm; length of tail, 84mm to 120mm; length of hind foot, 18mm to 22mm; length of ear, 13.4mm to 20.0mm; greatest length of skull, 22.7mm to 25.9mm and zygomatic breadth, 11.2mm to 13.5mm. Adults weigh between . Females weigh slightly more than males and are significantly larger in body length, ear length, length of mandible, and bullar width of skull. Cactus mice can be identified by having naked soles on their hind feet and almost naked flesh-colored tails (as opposed to the furry bicolored tail common in most ''Peromyscus'' species), which are usually the same length or longer than the animals' body length. Their ears are nearly hairless, large, and membranous. Their fur is long and soft; coloration varies between subspecies and between different populations. Color of fur varies from

ochre Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced ...

to cinnamon, with white ventral areas, and the sides and top of head slightly grayish. Females tend to be slightly paler in color than males, while juveniles appear more gray than their parents.

Distribution

Cactus mice are found in dry desert habitats, steppe, and mountain foothills in arid regions of the southwestern United States and northern Mexico, as well as islands off the coast of the Baja California peninsula and in the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

. Low average temperatures and lack of the mesquite species ''

Prosopis juliflora ''Prosopis juliflora'' ( es, bayahonda blanca, Cuji Venezuela, Trupillo Colombia, Aippia Wayuunaiki and long-thorn kiawe in Hawaii) is a shrub or small tree in the family Fabaceae, a kind of mesquite. It is native to Mexico, South America and ...

'' might limit northern expansion. The cactus mouse occurs sympatrically with five other mouse species, including the

California mouse The California deermouse or California mouse (''Peromyscus californicus'') is a species of rodent in the subfamily Neotominae in the family Cricetidae. It is the only species in the ''Peromyscus californicus'' species group. It is found in nort ...

canyon mouse The canyon mouse (''Peromyscus crinitus'') is a gray-brown mouse found in many states of the western United States and northern Mexico. Its preferred habitat is arid, rocky desert. Vegetation has little or no effect on the distribution of canyon ...

Eva's desert mouse Eva's desert mouse (''Peromyscus eva'') is a species of rodent in the genus ''Peromyscus'' of the family Cricetidae found only in the Baja California peninsula of Mexico.Musser, G. G. and M. D. Carleton. 2005. Superfamily Muroidea. Pp. 894-1531 ' ...

mesquite mouse The mesquite mouse (''Peromyscus merriami'') is a species of rodent in the family Cricetidae found in Mexico and in Arizona in the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or U ...

, and the

western deermouse The western deermouse or western deer mouse (''Peromyscus sonoriensis'') is a rodent native to North America. It is widespread throughout the western half of the continent, mainly in areas west of the Mississippi River. Taxonomy It was formerl ...

Diet

The cactus mouse feeds on seeds, mesquite beans, hackberry nutlets, insects, and green vegetation. In winter, they rely more on insects; on seeds and flowers in the spring; and seeds, leafy greens, and insects in the summer. In autumn, they transition to their winter diet.

Behavior

Cactus mice, like most

muroid The Muroidea are a large superfamily of rodents, including mice, rats, voles, hamsters, lemmings, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitats on every continent except A ...

s, exhibit

crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of daylig ...

behavior and may even appear in midday, but are mainly

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

. They may be less active during the full moon. They have been described as "shy and excitable, and seldom bites when handled". They vocalize a shrill, high pitched squeak when frightened. In laboratory studies, cactus mice average a running speed of . Compared to other ''Peromyscus'' species, cactus mice have a lower metabolism. This is thought to be an adaptation to arid environments, and maintained by lower activity of the

thyroid gland The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobe (anatomy), lobes. The lower two thirds of the lobes are connected by a thin band of Connective tissue, tissue cal ...

. They may enter

torpor Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. The term "torpor" can refer to the time ...

when deprived of food in the winter, and food and/or water in the summer. Below , they enter torpor more slowly, which may partially explain their southern distribution. In the laboratory, onset of torpor was observed to occur within half an hour of food deprivation. They are important as seed predators and as prey items for other animals.

Reproduction

The mating habits of cactus mice are currently not well studied, but are inferred from other ''Peromyscus'' species to be promiscuous. They mate year around, but more so during warmer months. Unlike other muroids, male cactus mice have a simple penis, rather than a complex one, and females have two pairs of

teat A teat is the projection from the mammary glands of mammals from which milk flows or is ejected for the purpose of feeding young. In many mammals the teat projects from the udder. The number of teats varies by mammalian species and often corre ...

s, rather than three. The number of teats in the female cactus mouse correlates with the number of offspring they can raise in their arid environment. Females mate after about two months, however, male sexual maturity age is unknown.

Relationship with humans

Cactus mice are ideal laboratory animals since they keep clean, live well in captivity, and have a high rate of productivity. They have been proposed for physiological and genetic studies. There are no known negative effects on humans or human-related activities. Specimens from Southern California have tested positive for hantavirus, however, infections in this species are likely incidental and localized, rather than a common reservoir.Journalof the Society Of Vector Ecologists, Volume 26, Issue 2, December 2001

References

{{Taxonbar, from=Q1768203

Cactus mouse The cactus mouse (''Peromyscus eremicus'') is a species of rodent in the family Cricetidae. It is a species of the genus ''Peromyscus'', a closely related group of New World mice often called "deermice" (although the term more commonly refers sp ...

Mammals of Mexico Mammals of the United States Rodents of North America Fauna of the Southwestern United States Fauna of the Baja California Peninsula Fauna of the California chaparral and woodlands Fauna of the Chihuahuan Desert Fauna of the Colorado Desert Fauna of the Sonoran Desert Fauna of Gulf of California islands Mammals described in 1858 Taxonomy articles created by Polbot