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woodland jumping mouse

Napaeozapus insignis

What do they look like?

Woodland jumping mice weigh between 17 and 26 g in the spring and early summer, and can weigh as much as 35 g during pregnancy or just before hibernation. Females are slightly larger than males. Total body length, from nose to end of tail vertebrae, is between 205 and 256 mm. These mice have white fur on their underparts, yellowish orange fur on their sides, and a dark stripe down their backs from nose to tail. The tops of their feet are white. Their tails are sparsely haired, thin, tapered, scaly, and white-tipped. Tail length is between 115 and 160 mm. The number and length of tail vertebrae is increased to make this length possible. These animals have four pairs of mammae . Woodland jumping mice are adapted to jumping, and so have long hind legs with elongated ankle bones and long toe bones. (Baker, 1983; Brower and Cade, 1966; Burt, 1946; Linzey and Brecht, 2002; Whitaker and Wrigley, 1972; Whitaker, 1963; Wrigley, 1972)

Sometimes woodland jumping mice may be confused with meadow jumping mice. However, woodland jumping mice have a white-tipped tail, are larger, and are more brightly tricolored than are meadow jumping mice. Also, woodland jumping mice are rarely found in open areas, whereas meadow jumping mice are generally found in open areas. (Baker, 1983)

In the northern portion of this species' range, woodland jumping mice are 12% larger in body size than they are in the south. Northern and eastern populations tend to be more yellowish and southern populations are reddish-orange. Northwestern populations have pale colored sides and dark backs. These distinctions in appearance and geographic differences helped Whitaker (1972) to identify five subspecies of woodland jumping mice. (Baker, 1983; Whitaker and Wrigley, 1972)

Woodland jumping mice have a basal metabolic rate of 1.8 ml O2/g hr. These animals regulate their body temperature with great precision when they are active. They undergo deep seasonal hibernation, and have a high lower critical temperature. They do not tolerate high temperatures well. These are likely adaptations to living in cold northern areas. (Brower and Cade, 1966)

  • Sexual Dimorphism
  • female larger
  • Range mass
    17 to 35 g
    0.60 to 1.23 oz
  • Range length
    205 to 256 mm
    8.07 to 10.08 in
  • Average basal metabolic rate
    1.8 cm3.O2/g/hr
  • Average basal metabolic rate
    0.22 W
    AnAge

Where do they live?

Woodland jumping mice are found throughout northeastern North America, from central Manitoba to northern Quebec and south into the lower Appalachian Mountains (northern Georgia). In Michigan, these mice may be found in the Upper Peninsula and in the northern three tiers of counties in the Lower Peninsula. (Baker, 1983; Brower and Cade, 1966; Burt, 1946; Whitaker and Wrigley, 1972)

What kind of habitat do they need?

Northern habitats which are dominated by conifers contain higher densities of woodland jumping mice than other habitats. These rodents prefer forested areas with dense woody undergrowth. Throughout their range, woodland jumping mice are found in spruce-fir and hemlock-hardwoods. They are also found at forest edges when these provide sufficient cover (shrubs, ferns, grasses, rocks) and access to water. Woodland jumping mice occur from sea level to elevation of 2013 m in the Appalachian highlands. (Baker, 1983; Brower and Cade, 1966; Whitaker and Wrigley, 1972; Wrigley, 1972)

Woodland jumping mice are found in a wide variety of habitats in Michigan. These include old growth dry and wet hardwoods, second growth hardwoods, mixed conifer swamp, tamarack and black spruce bog, second-growth fir and spruce, and in grassy areas with second-growth ash cover. (Baker, 1983)

  • Range elevation
    0 to 2013 m
    0.00 to 6604.33 ft

How do they reproduce?

Males come out of hibernation about 2 weeks before females, and mating occurs as soon as the females emerge. Mating can also place again in mid- to late- summer, in which case it produces a second litter. There is not much information available on the mating system of woodland jumping mice. In captivity, females sometimes injure the ears and tails of males who pursue them for mating. However, captive woodland jumping mice are generally passive with each other, even while breeding. (Wrigley, 1972)

Female woodland jumping mice are ready to breed when they emerge from hibernation in early- to mid-May. Litters can born between May and September, but most are born in June and August. The earliest record of pregnancy is May 8, but most females do not reproduce until June. Mice in the southern part of the range often produce two litters per year, with many females giving birth to their second litters in August. There are usually fewer young born in second litters than in first litters. The latest recorded pregnancy is September 1. By fall, as many as 70% of the individuals in a population of woodland jumping mice are young born that year. Both females and males are reproductively mature when they emerge from hibernation the year following their birth. (Baker, 1983; Burt, 1946; Whitaker and Wrigley, 1972; Wrigley, 1972)

Jumping mice develop more slowly than other rodents. It is possible that they need extra time for the growth and coordination of their very specialized jumping limbs. Litters contain from 1 to 7 young, and pregnancy lasts from 23 to 29 days. At birth, young are blind, naked, unpigmented, and weigh about 1 g. By the age of 10 days, young woodland jumping mice have pigment spots beneath the skin all over the body. Their bodies are covered with fine hair by day 14. Young jumping mice are fully furred by 24 days and their eyes open by 26 days. By day 34, the young are weaned and they have the appearance of adults, except they are smaller and their sides are yellowish brown (adults have orange-brown sides). Juveniles lose their yellowish fur when they molt, at about 63 to 80 days after birth. Most adults go through their yearly molt in August. (Baker, 1983; Burt, 1946; Whitaker and Wrigley, 1972; Wrigley, 1972)

  • How often does reproduction occur?
    Woodland jumping mice breed once or twice in one season (May through September).
  • Breeding season
    Mating occurs immediately after woodland jumping mice emerge from hibernation in early May. Mating may also occur in mid-summer (second litter).
  • Range number of offspring
    1 to 7
  • Average number of offspring
    4.5
  • Average number of offspring
    4
    AnAge
  • Range gestation period
    23 to 29 days
  • Average weaning age
    34 days
  • Range age at sexual or reproductive maturity (female)
    8 (low) months
  • Average age at sexual or reproductive maturity (female)
    11 months
  • Range age at sexual or reproductive maturity (male)
    8 to 11 months

Little is known about the parental care of woodland jumping mice because they are extremely difficult to observe in the wild, and most captive females kill their young shortly after they are born. Females care for the young, have smaller home ranges than males, have been observed covering the nest entrance during the day, and have been found in nests with their young. Because of their long developmental period, these mice provide a longer period of parental care than do many other small northern mice. The role of males in parental care is unknown. (Baker, 1983; Wrigley, 1972)

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

How long do they live?

Members of the jumping mice family have relatively long lifespans. For example, Brown (1970) estimated that western jumping mice live at least 4 years in the wild. Even though woodland jumping mice have a high turnover rate in the fall, with a maximum life span of 4 years, they live longer in the wild than most other North American small mammals. The average lifespan is 3 years. The long lifespan of these animals is at least partly due to their ability to hibernate. However, because age is estimated the amount of wear on molars, and because N. insignis only uses its teeth for half of the year, determining age can be difficult. (Baker, 1983; Whitaker and Wrigley, 1972; Wrigley, 1972)

How do they behave?

Woodland jumping mice are normally active at night, but may be active during the day, especially on cloudy or rainy days. These animals seek shelter in burrows they dig for themselves, burrows of other small mammals, or under shrubs. During the day, woodland jumping mice cover the entrance to their burrows. A tunnel may be 1.5 m in length. A globular nest is built in a small tunnel, in brush, or on the ground. The nest is made of grass and dead leaves, and can be as large as 154 mm in diameter. (Baker, 1983; Burt, 1946; Linzey and Brecht, 2002; Whitaker and Wrigley, 1972)

Normally, woodland jumping mice use a four-legged walk when moving around. However, when speed is needed they resort to a four-legged hopping locomotion. A hop normally covers 0.6 to 0.9 m, but can be as long as 1.8 m and as high as 0.6 m. Jumping mice travel along trails created by other small mammals, but not nearly as regularly as do meadow voles. Woodland jumping mice can climb within bushes and on vines but are not arboreal. Lastly, they can swim underwater and on the surface for short distances. (Baker, 1983; Burt, 1946; Whitaker and Wrigley, 1972; Wrigley, 1972)

Woodland jumping mice hibernate for at least six months of the year. They spend September/October until May in a subterranean burrow. Young do not enter hibernation until late October, about one month after adults begin hibernation. Body fat is quickly accumulated several weeks before entering hibernation. An adult that weighs 20 g in the summer may gain up to 10 g to in preparation to hibernate. While hibernating, woodland jumping mice curl up in a ball in their underground nests and enter a torpor where their normal body temperature of 37 C drops considerably. Finally, up to 35% of their weight is lost during hibernation. (Baker, 1983; Whitaker and Wrigley, 1972)

Woodland jumping mice can be nervous in captivity. Tail drumming and sporadic jumping are signs of excitability or nervousness. After about a month of captivity, woodland jumping mice calm sown and are easy to handle. These animals are not usually aggressive toward each other, and do not fight over food. When given the choice, they prefer to sleep in the same nest box as other woodland jumping mice. (Baker, 1983; Wrigley, 1972)

Home Range

Territory sizes of small rodents are hard to determine because it is hard to observe the animals directly in nature. Therefore, little is known about the territory size and territorial behavior of woodland jumping mice. Repeated captures of the same individuals do not happen enough times to estimate home range size accurately. Also, these mice frequently move to new areas. In spite of these difficulties, researchers estimate that males have home ranges between 0.4 and 3.6 hectares, and female ranges are between 0.4 and 2.6 hectares. Ranges of females and males overlap. Woodland jumping mice are highly mobile, a characteristic which helps them find food. Temporary food sources, such as ripened berries, attract relatively high numbers of woodland jumping mice. Apparent evidence of colonialism in these mice may actually be temporary congregations around a food source. The number of woosland jumping mice in any area can vary, but is usually between 0.64 and 59 individuals per ha. (Baker, 1983; Hanney, 1975; Whitaker and Wrigley, 1972; Wrigley, 1972)

How do they communicate with each other?

Not much is known about the communication in woodland jumping mice. In captivity, individuals are very tolerant of each other and show few signs of aggression. Individuals are normally silent; however young mice are constantly squeaking and making suckling sounds shortly after being born. Adults utter a soft clucking sound while sleeping or just before hibernation.

Although not specifically reported for this species, there is undoubtedly tactile communication between mates, as well as between mother and offspring. It is also likely that, as in other small rodents, chemical signals pass between individuals helping to identify individuals, sexes, and the reproductive condition of any particular mouse. (Baker, 1983; Whitaker and Wrigley, 1972; Wrigley, 1972)

What do they eat?

Woodland jumping mice eat a variety of foods, including fruits, seeds, fungi, and insects. In many areas, these mice depend on the fungus Endogone for food. This fungus was found in 78% of the mice examined, and made up about 40% of what they had eaten. This large percentage of consumed Endogone is not found in any other small mammal. These mice were also found to have eaten raspberries, May apples, blueberries, ferns, leaves, and nuts. Insects are another important part of the diet of these mice, providing about 22% of their food. Woodland jumping mice do not cache food. (Connor, 1966; Linzey and Brecht, 2002; Linzey and Linzey, 1973; Whitaker and Wrigley, 1972)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • terrestrial worms
  • Plant Foods
  • leaves
  • roots and tubers
  • seeds, grains, and nuts
  • fruit
  • bryophytes
  • Other Foods
  • fungus

What eats them and how do they avoid being eaten?

The three-colored pattern found on the fur of woodland jumping mice helps to conceal these animals against dead vegetation. If they are pursued by predators, woodland jumping mice escape by jumping quickly, then remaining still for a little while. Their coloration, escape behavior, and relative lack of odor are probably all ways they avoid predators. Woodland jumping mice are mostly safe from predators during hibernation. Timber rattlesnakes, broad-banded copperheads, screech owls, bobcats, minks, striped skunks, gray wolves, and house cats are all known predators of woodland jumping mice.

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

Woodland jumping mice eat fungi and help to disperse mycorrhizal fungi. Mycorrhizal fungi are very important to the ecosystem because they provide trees with nutrients. They also break down detritus. Woodland jumping mice are often found with other small mammals, such as white footed mice. In contrast, woodland jumping mice are rarely found in the same areas as southern red-backed voles. This may be due to aggression and not competition for resources. (Baker, 1983; Wrigley, 1972)

Woodland jumping mice have many external parasites, including fleas, mites, chiggers, ticks, and botflies. One species of mite, is the most common external parasite of woodland jumping mice. There can be as many as several hundred of these mites per mouse. Red mites are also found on woodland jumping mice. Internal parasites include protozoans, cestodes or tapeworms, and nematodes or roundworms. (Baker, 1983; Linzey and Brecht, 2002; Whitaker and Wrigley, 1972; Whitaker, 1963; Wrigley, 1972)

  • Ecosystem Impact
  • disperses seeds
Species (or larger taxonomic groups) used as hosts by this species
  • none
Species (or larger taxonomic groups) that are mutualists with this species
  • none

Do they cause problems?

There are no known adverse affects of woodland jumping mice on humans.

How do they interact with us?

Little is known about how woodland jumping mice benefit humans. The disperal of mycorrhizal fungi by these animals benefits many species of trees, some of which may be economically important.

Are they endangered?

Woodland jumping mice have no special status on the IUCN Red List, US Federal List, or CITES.

Some more information...

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Erin Harrington (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Baker, R. 1983. Michigan Mammals. Detroit, Michigan: Michigan State University Press.

Brower, J., T. Cade. 1966. Ecology and Physiology of Napaeozapus insignis (Miller) and Other Woodland Mice. Ecology, 47/1: 46-63.

Brown, L. 1970. Population dynamics of the western jumping mouse (Zapus princeps) during a four-year study. Journal of Mammalogy, 51: 651-658.

Burt, W. 1946. The Mammals of Michigan. Ann Arbor, Michigan: The University of Michigan Press.

Connor, P. 1966. The mammals of the Tug Hill Plateau, New York. New York State Museum and Science Service Bulletin, 406: 1-82.

Costello, R., A. Rosenberger. 2003. "Napaeozapus insignis, Woodland Jumping Mouse" (On-line). Smithsonian National Museum of Natural History: North American Mammals. Accessed March 29, 2004 at http://web4.si.edu/mna/image_info.cfm?species_id=207.

Hanney, P. 1975. Rodents: Their Lives and Habits. New York, New York: Taplinger Publishing Company.

Linzey, D., C. Brecht. 2002. "Napaeozapus insignis (Miller)" (On-line). Mammalia: Mammals of Great Smoky Mountains National Park. Accessed March 29, 2004 at http://www.discoverlife.org/nh/tx/Vertebrata/Mammalia/Dipodidae/Napaeozapus/insignis/.

Linzey, D., A. Linzey. 1973. Notes on food of small mammals from Great Smoky Mountains National Park, Tennessee-North Carolina. Journal of the Elisha Mitchell Scientific Society, 89/1: 6-14.

Walker, E. 1964. Mammals of the World. Baltimore, Maryland: Johns Hopkins Press.

Whitaker, J. 1963. Food, habitat, and parasites of the woodland jumping mouse in central New York. Journal of Mammalogy, 44/2: 316-321.

Whitaker, J., R. Wrigley. 1972. Napaeozapus insignis. Mammalian Species, No. 14: 1-6.

Wilson, D., D. Reeder. 1993. "Napaeozapus insignis" (On-line). Mammal Species of the World (MSW). Accessed March 28, 2004 at http://www.nmnh.si.edu/msw/.

Wrigley, R. 1972. Systematics and Biology of the Woodland Jumping Mouse Napaeozapus insignis . Illinois University Biological Monographs, 47: 1-118.

 
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Harrington, E. 2004. "Napaeozapus insignis" (On-line), Animal Diversity Web. Accessed November 22, 2017 at http://www.biokids.umich.edu/accounts/Napaeozapus_insignis/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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