Deer mice have small bodies. They weigh between 10 and 24 grams and they are typically 119 to 222 mm long, no longer than house mice. Tail length varies in different populations and ranges from 45 mm to 105 mm. Deer mice that live in woodlands are typically larger and have larger tails and feet than deer mice that live in prairies. Deer mice have round and slender bodies. The head has a pointed nose with large, black, beady eyes. The ears are large and have little fur covering them. The whiskers are long and prominent. Deer mice have shorter forelimbs than hind limbs.
Deer mice are grayish to reddish brown with white underparts. The fur is short, soft, and dense. The finely-haired tail is dark on top and light on the bottom, with a sharp division between the two colors. This differs from white-footed mice, where the separation of the two colors on the tail is less distinct. There are other characteristics that help distinguish deer mice from the similar white-footed mice. Deer mice generally have hind feet that are 22 mm or less, while white-footed mice usually have hind feet 22 mm or more. Also, deer mice are more richly colored with a brownish or tawny coat, whereas white-footed mice tend to be more pinkish-buff or grayish, with scattered dark hairs. These characteristics vary depending on location, however, and in some areas the two species are extremely hard to tell apart based on outward appearance.
Deer mice are common in North America. They are distributed from the northern tree line in Alaska and Canada southward to central Mexico. They are absent from the southeastern United States and some coastal areas of Mexico within this range.
Deer mice live in many different habitats throughout their range. They can be found in alpine habitats, northern boreal forest, desert, grassland, brushland, agricultural fields, southern montane woodland, and dry upper tropical habitats. Also, deer mice are found on boreal, temperate, and tropical islands. However, their most common habitats are prairies, bushy areas, and woodlands.
Deer mice are polygynous, meaning that male deer mice each mate with more than one female.
Females deer mice can have many litters in a year. In the wild, reproduction may not occur during winter or other unfavorable seasons. Females are able to become pregnant again shortly after giving birth. The pregnancy of a female deer mouse that is not nursing young lasts from 22.4 to 25.5 days and the pregnancy of a female deer mouse that is nursing young lasts 24.1 to 30.6 days. Deer mice may have litters containing from one to eleven young with typical litters containing four, five, or six babies. Litter size increases each time a female deer mouse gives birth until the fifth or sixth litter and decreases afterwards.
Deer mice are very helpless at birth but develop quickly. At birth, each baby has a mass of about 1.5 g. The young are born hairless with wrinkled, pink skin, closed eyes, and folded over ears. Juvenile hair begins to develop on the second day after birth. On the third day, the ears unfold with the ear canal opening on the tenth day. Eyes open on the fifteenth day, and the young are weaned between day 25 and 35.
Deer mice can reproduce when they are 35 days old, but they usually breed for the first time at 49 days.
Like all female eutherian mammals, deer mice provide nourishment to their young before birth through the placenta. After the young are born, mother deer mice produce milk for their offspring. While nursing, the mother carries her young clinging to her nipples or one at a time in her mouth. Once weaned, the young usually leave the nest and become independent of their mother, although sometimes the mother will tolerate their presence for longer periods. Often when the mother has a second litter, she forces the first litter out of the nest.
In captivity, deer mice can live as long as eight years. However, in the wild, life expectancy is much shorter, usually less than a year.
Deer mice are most active at night. They spend most of their time on the ground but they are also adept climbers. Activity centers around a nest and food stockpile. Deer mice that live in prairies construct nests just below ground level in their own burrows or those abandoned by other animals. Forest dwelling deer mice construct nests near the ground in stumps, logs, brush piles, tree cavities, reconstructed bird nests, tree bark, or even cottages or outbuildings. Nests are made of rounded masses of plant matter (as much as 100 mm in diameter).
An adult male, a few adult females, and several young make up the basic social unit of the deer mouse. In the winter, groups of ten individuals or more of mixed sexes and ages may huddle together in nests to conserve heat. Also during winter, deer mice may enter a sluggish state called torpor to reduce body temperature and conserve energy.
Home ranges of deer mice range from 242 square meters to 3000 square meters. Home ranges of males are larger than females and show more overlap. Males use their home ranges for both access to feeding and nesting and also to reproductive females. Females use their home ranges for feeding, nesting, and rearing young.
Females raising young are more aggressive in territory defense than males, and their territories overlap less, suggesting that they have more at stake in territory defense than males. Intruding deer mice will kill young that are unattended by a female.
Deer mice have large eyes and ears as well as keen noses and long whiskers for perceiving their environment. They communicate by grooming one another, posturing with their bodies, producing scent, and making a variety of squeaky noises. Sometimes when disturbed they drum their front paws rapidly up and down against a hard surface. This may serve as a warning signal to other deer mice.
Deer mice are omnivorous. They eat a wide variety of plant and animal matter depending on what is available, including insects and other invertebrates, seeds, fruits, flowers, nuts, and other plant products. Deer mice sometimes eat their own feces, a practice called coprophagy. In cooler climates, deer mice hide food in secret stockpiles during the autumn months.
Deer mice are important for spreading seeds of many types of plants and the spores of fungi. They are also an important food source for various predators.
Deer mice eat seeds of valued forest trees, sometimes preventing the trees from growing back. In addition, deer mice can be destructive by raiding stored grains and other food supplies, gathering litter, and gnawing. Finally, deer mice are hosts for strain of hantavirus called Sin Nombre virus (also called Four Corners or Muerto Canyon virus). This virus, which can be transferred to humans from deer mice, causes an often deadly disease known as hantavirus pulmonary syndrome.
Deer mice provide food for a number of carnivores, some of which are economically valuable fur-bearing mammals. Also, deer mice eat some insects that are considered pests.
Deer mice are abundant, often among the most abundant mice of certain areas. Densities can reach 11 mice per acre. Many factors including availablity of food, water, and nest sites are thought to affect how many deer mice can live in an area. However, only the availability of food has been studied in enough detail to show it has an effect on population density.
In Michigan, there are three distinct types of deer mouse. One of these is found only on Isle Royale. Another, the woodland deer mouse, is found in forests of the northern Lower Peninsula and the Upper Peninsula. The third, the prairie deer mouse, is found in open areas (preferably farm fields, early stages of grasslands, or along lake shores) of the Lower Peninsula and the southwestern Upper Peninsula. Woodland and prairie deer mice differ quite noticeably. Woodland deer mice have longer tails, ears, skulls, and hind feet than prairie deer mice. It is interesting that despite having overlapping ranges these types of deer mice do not interbreed. One possible explanation for this is the difference in their habitats, making it unlikely for them to meet.
Allison Poor (editor), University of Michigan-Ann Arbor.
Andrew Bunker (author), University of Michigan-Ann Arbor.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
living in landscapes dominated by human agriculture.
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
Referring to an animal that lives in trees; tree-climbing.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
animals that generate their own body heat through metabolic processes.
union of egg and spermatozoan
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
animals that have little or no ability to regulate their body temperature, body temperatures fluctuate with the temperature of their environment, often referred to as 'cold-blooded'.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
an animal that mainly eats all kinds of things, including plants and animals
chemicals released into air or water that are detected by and responded to by other animals of the same species
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
having more than one female as a mate at one time
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
scrub forests develop in areas that experience dry seasons.
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
places a food item in a special place to be eaten later. Also called "hoarding"
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
breeding takes place throughout the year
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