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Reithrodontomys montanusplains harvest mouse

By Benjamin Brand

Geographic Range

Montane harvest mice live in the dry uplands of the Great Plains. They are found in southwestern South Dakota and southeastern Montana south thruough eastern Wyoming, Colorado, and New Mexico, all of Nebraska and Kansa and most of Oklahoma and Texas. Also found in southern Arizona and northern Mexico in the extremes of its range.

Habitat

These mice appear to prefer climax, or nearly climax, well-drained grassland. They are in the highest densities in shorter grasses, but are found in lower numbers in taller grasses. Reithrodontomys montanus builds its nest out of grasses and places the nest slightly above the ground in grasses or shrubs, or on the ground. The species has also been known to take over a bird's nest for its own. In areas with human contact Reithrodontomys montanus has been found in tin cans or other suitable nests.

  • Range elevation
    80 to 1900 m
    262.47 to 6233.60 ft

Physical Description

Reithrodontomys montanus is a small mouse with grayish-brown fur. It has a white underside and a dark stripe down the middle of the back. The tail of this species ranges from 20 to 69 mm and is always shorter than the head and body. The tail is also striped and has sparse fur, yet does not appear scaly. Reithrodontomys means "groove toothed mouse" and refers to a groove that is found in the upper incisors. This groove easily distinguishes this genus from others occuring in the same area.

  • Range mass
    6 to 13 g
    0.21 to 0.46 oz
  • Range length
    54 to 146 mm
    2.13 to 5.75 in
  • Average length
    116 mm
    4.57 in

Reproduction

Females have 6 mammae. Males have seminal vesicals, preputial glands, ampullary glands, penial spines, and a baculum. Young are born naked and blind. They are well haired at 6 days and their eyes open at 8 to 13 days. Adult size is reached in 5 weeks. Reithrodontomys montanus goes through 2 changes in pelage before reaching adulthood. The juvenile hair is cottony and duller in color. Sub-adult pelage is the same color as adults but the hair is less dense. Males reach sexual maturity at 2 months, while females reach sexual maturity at about 12 weeks

  • Breeding season
    Females give birth year round
  • Range number of offspring
    1 to 9
  • Average number of offspring
    4
  • Average gestation period
    21 days
  • Average weaning age
    21 days
  • Range age at sexual or reproductive maturity (female)
    8 to 12 weeks
  • Range age at sexual or reproductive maturity (male)
    8 to 12 weeks

Behavior

Communication and Perception

Food Habits

Reithrodontomys montanus often stores food underground for use during severe winters. It eats: seeds, flowers, grasses, cactus fruits, and insects such as grasshoppers.

  • Animal Foods
  • insects
  • Plant Foods
  • seeds, grains, and nuts
  • fruit
  • flowers

Predation

Ecosystem Roles

Reithrodontomys montanus is often found in association with many other rodents, however it is usually the least abundant in its communities.

  • Ecosystem Impact
  • disperses seeds

Conservation Status

This species is considered common.

Other Comments

This species was first discovered by Baird in 1855. The discovery was made in a mountainous region of Colorado which led to the species montanus. Later, however, its distribution was found to be the Great Plains, far from any mountains.

Contributors

Benjamin Brand (author), University of Michigan-Ann Arbor, Bret Weinstein (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

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.

World Map

altricial

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.

bilateral symmetry

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. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

iteroparous

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).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

terrestrial

Living on the ground.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

"New World Mice And Rats (Family Cricetidae)" (On-line). Accessed November 17, 2001 at http://www.ukans.edu/~mammals/reithro-mont.html.

"Oklahoma Museum of Natural History" (On-line). Accessed November 17, 2001 at http://www.omnh.ou.edu/mammalkey/Reithrodontomys4.html.

1997. "The Mammals of Texas (Online Edition)" (On-line). Accessed November 17,2001 at http://www.nsrl.ttu.edu/tmot1/reitmont.htm.

Hayssen, V., A. van Tienhoven, A. van Tienhoven. 1993. Asdell's Patterns of Mammalian Reproduction. Ithaca, NY: Cornell University Press.

Wilkins, K. 16 June 1986. Reithrodontomys montanus. Mammalian species, 257: 1-5.

Wilson, D., S. Ruff. 1999. The Smithsonian book of North American mammals. Washington D.C.: Smithsonian Institution Press in association with the American Society of Mammalogists.

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