Western jumping mice are found throughout western Canada and much of the western United States.
Western jumping mice are found primarily in moist fields, thickets, and woodlands, especially where grasses, sedges, or other green plant cover is dense. They are also found in grassy edges of streams, ponds, and lakes, usually within 50 meters of water.
Western jumping mice have yellow sides with a dark band down the middle of their back. Their belly is usually white, but can sometimes have a yellow tinge. The body length including the tail is 215-260 mm. They have a long tail (126-160 mm) that is darker on the top than the bottom. Males and females are similar in size and characteristics. Weight ranges from 18 to 24 grams, but can reach up to 35 grams before they enter hibernation. The hind feet are very large with each foot measuring 28-34 mm and they can hop up to 2 m. Each upper tooth row has 4 molariform teeth with the first reduced in size.
Little is known about mating behavior in Z. princeps.
The timing of reproduction for Western jumping mice varies from year to year. Many females less than 2 years old do not breed. If they do breed it will usually occur later in the season and they produce smaller litter sizes than older females.
Western jumping mice mate soon after they emerge from hibernation, usually in June. Their gestation period is approximately 18 days and they give birth to 3 to 9 young. A newborn weighs about 1 gram. They can have 2 or 3 litters per year but will usually have only one litter. Young born too late in the year do not acquire sufficient fat reserves to survive hibernation.
The young are born in a well-developed spherical nest 15-20 cm in diameter with no obvious entrance. The nest is interwoven with broad-leaved grasses, sedges, and other plant fibers, and located in a depression in the ground usually less than 30 cm below the soil surface.
(Falk et. al. 1987, Brown 1967)
Young are born helpless and are cared for in the nest by their mother until weaned.
Western jumping mice can live as long as 6 years if they survive their first season of hibernation. Half of all juveniles that enter their first winter hibernation will die. Because Western jumping mice hibernate they are only active for a short period each year.
Western jumping mice are primarily nocturnal, however they will also forage in the daytime. They live in burrows dug by themselves or other animals. Fat deposition begins 1 month prior to hibernation. When alarmed, Western jumping mice will drum their tails on the ground. If startled from their hiding place, they may make a series of jumps 90–150 cm long, disappearing by remaining motionless in a new spot. They tend to use the runways of other animals rather than making their own. They can swim and climb. Little is known about the social behavior of these animals.
(Belk et. al. 1988)
Western jumping mice need high-energy foods to increase fat storage for their long hibernation periods. The main foods eaten by Western jumping mice are arthropods, seeds and leaves. Seeds are important in the fat deposition, however, arthropods may be a critical substitute when seeds are not available.
(Vaughan et. al. 1980)
Western jumping mice exhibit low predation by mammalian carnivores during hibernation. One of the reasons for this is that their hibernation chambers are hidden far beneath the layers of snow. Also, jumping mice give off little odor during hibernation, making them difficult find.
Western jumping mice are important prey species for many predators in the ecosystems in which they live. They are also important as consumers of seeds and arthropods.
Z. princeps is an important component of healthy grass-dominated habitats throughout their range.
Western jumping mice are common within their range.
The family name was changed in 1996 from Dipodidae to Zapodidae.
Rachel Mockler (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.
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.
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.
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.
uses smells or other chemicals to communicate
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.
parental care is carried out by females
union of egg and spermatozoan
fertilization takes place within the female's body
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.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
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.
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
Belk, M., H. Smith, J. Lawson. 1988. Use and partitioning of montane habitat by small mammals. Journal of Mammology, 69: 688-695.
Brown, L. 1970. Population dynamics of the western jumping mouse (*Zapus princeps*) during a four-year study. Journal of Mammology, 51: 651-658.
Brown, L. 1967. Seasonal activity patterns and breeding of the western jumping mouse (*Zapus princeps*) in Wyoming. American Midland Naturalist, 78: 460-470.
Falk, J., J. Miller. 1987. Reproduction by female *Zapus princeps* in relation to age, size and body fat. Canadian Journal of Zoology, 65: 568-571.
Knopf, A. 2000. "eNature.com" (On-line). Accessed October 23, 2001 at http://www.enature.com/fieldguide.
Meyers, L. 1969. Home range and longevity in *Zapus princeps* in Colorado. American Midland Naturalist, 82: 628-629.
Vaughan, T., W. Weil. 1980. The importance of arthropods in the diet of *Zapus princeps* in a subalpine habitiat. Journal of Mammology, 61: 122-124.