The star-nosed mole has a rose-colored ring of fleshy, retractable tentacles surrounding its nose. This nasal disc is bilaterally symmetrical with 11 projections on each side. Equally distinct is the scaly, fleshy tail that is covered with concentric rings and short, coarse hairs. The tail, nearly as long as the combined length of the head and body, is constricted at the base, tapered at the tip, and during the winter swollen in size, when it serves as a fat storage organ. The eyes of this species are larger than those of the hairy-tailed mole, and its blackish-brown to black fur is longer, the metallic sheen absent. The limbs are short, and the front feet are paddlelike with long, stout claws. The surfaces of the pinkish-colored feet possess dark scales. An average sized star-nosed mole is 19 mm (7.6 in) in length and weighs 50 g (1.8 oz).
(Condylura cristata Linnaeus)
From: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp
Range and Habitat
The range is from southeastern Manitoba to Labrador and Nova Scotia, south and east to southeastern Georgia. The star-nosed mole prefers damp to saturated soils, and often lives in the organic muck adjacent to water. Grassy meadows, marshes, swamps, and deciduous, coniferous, and mixed forests are some of the Adirondack plant communities in which it resided, to elevations of at least 573 m (1880 ft).
The tunnels of this species are 3-6 cm (1.2-2.4 in) in diameter and extend from just below the surface of the ground to a depth of 60 cm (24 in). Individuals living in wet soils burrow above and below the water table, and moles near water usually have tunnels that open at, or below, the water surface. Enlarged, dry sections of the tunnels serve as sites for resting and brood-rearing nests which the moles build by collecting dry leaves or grass. Sometimes a mole will build its nest where a tunnel passes beneath a stump or log. Each nest chamber is an oblong cavity 13-18 cm (5-7 in) wide and 8-13 (3-5 in) in height.
Food and Feeding Behavior
This mole pushes its way through the surface layers of soil to catch invertebrates such as beetle larvae and earthworms. However, star-nosed moles living near water acquire only 12-25 percent of their food in this fashion, taking the rest underwater. Aquatic insects and annelids form the bulk of the diet with mollusks, crustacea, small amphibians and fish making up the remainder. Bottom-dwelling aquatic invertebrates are the principal winter foods of star-nosed moles living near water. They readily enter water, even swimming beneath the ice, foraging by probing bottom sediments with their fleshy tentacles which are laden with touch receptors.
Activity and Movement
Large molehills mark the home ranges of a star-nosed mole, which is both fossorial and semiaquatic. Like other moles, it digs with the broad front feet while the hind feet push against the sides, stopping periodically to shove the loose soil to the surface where it creates a mound 30-61 cm (1-2 ft) wide and 15-23 cm (6-9 in) deep - much larger than the mounds of the hairy-tailed mole. Its excavation rate is about 2-3 m (7-8 ft) per hour. When swimming, the star-nosed mole paddles first with one front foot, then the other, extending an opposing foot synchronously, barely moving the tail or waving it in shallow, lateral arcs and perhaps using it to steer. Frequent trips to the surface for air alternate with dives that last about 10 seconds.
None of the Adirondack insectivores hibernate, nor is this species an exception. Unlike Parascalops, the star-nosed mole tunnels through, and even moves on the surface of snow. Although normal progression on the surface of the ground or snow is slow, an alarmed star-nosed mole can run short distances at speeds of 6.4-8 km (4-5 mi) per hour. This species is active by day as well as by night, spending about half of each 24 hour period resting or sleeping curled upright with the head bent under the forelimbs.
The breeding biology of this species, especially Adirondack populations, is not well known. Females probably bear but one litter of 2-7 (average 5) young between late April and early July, a few as late as August. The gestation period is approximately 45 days. Wrinkled, pale pink, blind, and hairless at birth, each newborn mole is 49 mm (1.9 in) in length and weighs no more than 1.5 g (0.05 oz). The nasal disc is at first enclosed in a thin membrane. Weaning and dispersal from the nest occur around day 21, sexual maturity, the following spring. The life span of the star-nosed mole is not known.
Raptors, including screech, great horned, long-eared, barred, and barn owls, and red-tailed hawks; mammals such as striped skunks, weasels, minks, and foxes; and fish such as the northern pike prey on this mammal.
- Social System - Mammalogists have taken pairs of star-nosed moles from the same tunnel system before the breeding season suggesting the possibility of monogamy but the mating system and social organization are unknown. Small patches of optimum habitat may contain large populations, while nearby areas of equally suitable terrain may be devoid of this mole, a condition which has led to the notion of it being colonial. Certainly, it may be gregarious and tolerant of conspecifics, e.g., where peak densities of 25-30 or more per ha (10-12 per acre) occur.
- Communication - How these mammals interact remains a mystery. Captives produce few vocalizations, but the relatively large external ear openings suggest a role for vocal signals. Vision is poor. Tactile and chemical cues are the most likely means of regulating social encounters. Glands e.g., on the throat, wrist, chin, and abdomen, are most active during the breeding season when their secretions leave a golden stain on the fur. Merriam (p. 152) described the odor of these glands as "exceedingly rank and nauseous!"
Eadie, W.R. and W.J. Hamilton, Jr. 1956. Notes on reproduction in the star-nosed mole. Journal of Mammalogy, 37:223-231.
Hamilton, W.J., Jr. 1931. Habits of the star-nosed mole, Condylura cristata. Journal of Mammalogy, 12:345-355.
Petersen, K.E., and T.L. Yates. 1980. Condylura crystata. Mammalian Species, 129.