Woodland Jumping Mouse
(Napaeozapus insignis Preble)
From: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.
Description: The large hind limbs, bright colors, and long, tapered, white-tipped tail identify the woodland jumping mouse. The 115-160 mm (4.5-6.3 in), sparsely-haired tail, grayish brown above, and white below accounts for two-thirds of the total length, 204-256 mm (8.0-10.1 in). The back is dark brown to black with yellowish guard hairs, the sides are yellowish orange with scattered, black guard hairs. The underparts are creamy white. Large individuals may weigh as much as 26 g (10.9 oz.). Brighter colors, fewer teeth, and the white-tipped tail (the white hair absent) distinguished the woodland from the meadow jumping mouse.Range and Habitat: The range is from southeastern Manitoba to southeastern Canada, the northeastern U.S., and south to northern Georgia. The woodland jumping mouse is a common resident of coniferous, deciduous, and mixed forests in the Adirondacks to elevations of 1189 m (3900 ft). It prefers habitats with dense herbaceous vegetation and shrubs, often near logs, moss- covered rock piles, and stream banks. Where red-backed voles are abundant, woodland jumping mice are usually absent. Forest edges adjacent to grassy meadows may harbor populations of both woodland and meadow jumping mice.
Unlike many small mammals, the woodland jumping mouse does not construct or travel elaborate runways and trails, although it may excavate burrows, sealing the entrances by day. Occasionally, it may use the abandoned burrows of other small mammals. The globular nest, 10-15 cm (4-6 in) in diameter, is made of plant fibers and may be underground, under a stump, or placed in a tangle of brush or roots.
Food and Feeding Behavior: Almost a third of the diet consists of subterranean fungi, e.g., Endogone, which the woodland jumping mouse excavates from the soil and leaf litter of the forest floor. Seeds, fleshy fruits, green leaves, roots, and invertebrates such as caterpillars, beetles, and spiders make up the remainder of the diet. This species does not cache food.
Activity and Movement: The woodland jumping mouse usually move by walking or hopping, but also leaps. When startled, it makes several erratic leaps, bounding .6 m (2 ft) into the air and covering .9-1.8 m (3-6 ft) with each leap, stopping suddenly beside a log or beneath a leaf. This combination of conspicuous movement and an abrupt halt may conceal the woodland jumping mouse from predators relying mainly on vision to capture prey. The long tail aids in balance when leaping or climbing shrubs. This species can swim but only for a few minutes, and it usually avoids water.
While chiefly nocturnal and more active during cool nights, foraging may occur on cloudy mornings or afternoons. After accumulating fat that may amount to as much as one-third of the total weight, individuals hibernate, adults becoming torpid in mid-September and juveniles in October. Males emerge first, in mid-April to mid-May, females approximately two weeks later.
Reproduction: Females bear litters of 1- 9 (average 4-5) young in June, and at least some produce a second, smaller litter in August or early September. The gestation period is 23-25 days. The young are born hairless and blind. Their eyes open at 26 days, and they are weaned at 34 days. They become sexually mature the following summer. The potential life span is 3-4 years, longer than for most rodents of comparable size.
Predators: Birds of prey (especially owls), snakes, members of the weasel family, and bobcats are some of the predators of woodland jumping mice.
- Social system: Little is known about the social interactions among individuals living in the wild. Home ranges of males vary from 0.4-3.6 ha (1-9 acres) and overlap those of females which are 0.4-2.6 ha (1-6.5 acres). Population densities vary appreciably within suitable habitat among years. A study of this species at Whiteface Mountain indicated a density of 12.8 individuals per ha (5.2/acre).
- Communication: Adults respond to disturbance by vibrating their tails (tail drumming). Adults and young “squeal” and adults produce a soft “clucking” sound when alarmed.
Brower, J.E. and T.J. Cade. 1966. Ecology and physiology of Napaeozapus insignis (Miller) and other woodland mice. Ecology, 47:46 63.
Ovaska, K. 1982. Microdistribution and spacing behavior in the woodland jumping mouse, Napaeozapus insignis (Miller). M.S. Thesis, Acadia Univ., Wolfville, Nova Scotia. 105pp.
Ovaska, K. and T.B. Herman. 1986. Fungal consumption by six species of small mammals in Nova Scotia. Journal of Mammalogy, 67:208 211.
Whitaker, J.O. and R.E. Wrigley. 1972. Napaeozapus insignis. Mammalian Species, 14, 6pp.
Wrigley, R.E. 1972 Systematics and biology of the woodland jumping mouse, Napaeozapus insignis (Miller). Illinois Biological Monographs, Univ. of Chicago Press, Urbana, 117pp.