Neurotrichus gibbsii is found in western North America, from mid-California to lower British Columbia. It ranges from the Pacific Ocean to the Cascade and Sierra Nevada mountains. Shrew-moles are also found on Destruction Island, Washington (Campbell, 2001).

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Northwestern North America, from southwestern British Columbia (Fraser River region) south through western Washington (including Destruction Island), western Oregon, and western California to Fremont Peak, Monterey County. To 2440 m in Washington.

N. gibbsii is the smallest species of New World Talpidae (Wilson and Ruff, 1999). Its hair is black or blue-black and not as plush as other moles (Dalquest, 1942). Shrew-moles' forefeet are slightly broadened, not webbed and modified for digging only (Wilson and Ruff, 1999). The external ears are absent. Eyes are greatly reduced, and these animals have a flat, elongated nose (Carraway, 1991). The tail is about half as long as the body and reasonably wide (Reed, 1951). N. gibbsii show no sexual diamorphism and its dental formula is 3/3, 1/1, 2/2, 3/3= 36 (Carraway, 1991).

Range mass: 8 to 14.5 g.

Average mass: 10 g.

Range length: 100 to 130 mm.

Average length: 120 mm.

Other Physical Features: endothermic ; bilateral symmetry

Length: 13 cm

Weight: 11 grams

• Terrestrial

N. gibbsii prefer soils that are easy to dig, and where there is plenty of organic matter. They are mostly found in the temperate rainforests of northwest North America, where soils are soft and deep. Shrew-moles can also be found in areas that are moist and weedy or brushy (Campbell, 2001).

Range elevation: sea level to 2500 m.

Habitat Regions: temperate

Terrestrial Biomes: rainforest

Comments: Washington: moist habitats with soft earth free of sod; lower elevation ravines with deep soils, much vegetative surface litter (logs, leaves), and big-leaf maple and other plants; less commonly in lakeshore willow thickets; rarely in drier habitats (Dalquest 1948). Oregon: most common in riparian alder and alder-salmonberry thickets; less commonly occurs in mature and immature conifer, riparian hardwood, sitka spruce-salal, skunkcabbage marsh, wet pasture, headland prairie, and headland scrub habitats (Maser et al. 1981); also montane areas with low cover of lichen and few snags, and Douglas-fir forest (see Carraway and Verts 1991). California: redwood, Douglas-fir, and yellow pine forests and forest edges, usually near streams (Ingles 1965). Constructs runways near surface of duff layer and deeper but shallow burrows, usually near streams. Less fossorial than other moles.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

N. gibbsii need a lots of food, compared to thier body size, because of their high metabolism. Dalquest (1942) observed that shrew-moles are capable of eating up to 1.4 times their own body weight in twelve hours and can die of starvation very quickly. He also observed that they use their nose to locate prey. He describes the process of a Shrew-mole walking up to the prey and "rapping" its nose on the ground right in front of the prey, then turning its head to the right and rapping on the ground again. It will repeate this motion, but turning its head to the left. These motions are repeated very quickly until the shrew-mole's nose touches the prey. Shrew-moles also use their long noses to push over insect pupae and isopods (Dalquest, 1942). N. gibbsii capture earthworms and other prey when they fall into the tunnels they dig. Earthworms are their prefered food (Yates,1982).

Foods eaten include: earthworms, insect larvae, snails, slugs, centipedes, sow bugs, fungus and seeds.

Animal Foods: insects; terrestrial non-insect arthropods; mollusks; terrestrial worms

Plant Foods: seeds, grains, and nuts

Primary Diet: carnivore (Vermivore)

Comments: May consume more than its own body weight in food in one day. Feeds primarily on earthworms, gastropods, centipedes, sowbugs, insects, and other invertebrates. Also eats some plant seeds, fungi, and lichens. Sightless; detects prey with snout.

Dalquest (1942) observed that if a Shrew-mole is scared into hiding, it will reemerge in search of food in less than a minute. This makes them an easy target for predators, though they are not the major diet of any species (Racey,1929). Owls seem to be their biggest predator (Carraway, 1991).

Known Predators:

• owls (Strigiformes)
• snakes (Serpentes)
• red-tailed hawks (Buteo jamaicensis)
• raccoons (Procyon lotor)
• swift foxes (Vulpes velox)
• coyotes (Canis latrans)
• domestic dogs (Canis lupus familiaris)
• domestic cats (Felis silvestris)
• gray foxes (Urocyon cinereoargenteus)
• red foxes (Vulpes vulpes)

Seems to be more social than other insectivores; may travel in loose bands (Dalquest and Orcutt 1942, Maser et al. 1981). Population density in favorable habitat estimated at 12-15/ha (but up to 247/ha after removal of all other small mammals) (Dalquest and Orcutt 1942).

Comments: Active throughout the year.

Mating System: polygynandrous (promiscuous)

Shrew-mole has a relatively long breeding season. Reproduction happens once a year and lasts from late February to August. The length of the gestation period is unknown, but is assumed to be at least four weeks long (Yates, 1982). The nests are built above ground, although one nest was observed in a stump about a meter off the ground (Dalquest, 1942). The babies are born blind and weigh less than a gram (Wilson and Ruff, 1999).

Breeding season: usually lasts from late February to August

Range number of offspring: 1 to 4.

Average number of offspring: 3.

Average gestation period: unknown minutes.

Parental Investment: altricial ; female parental care

Most breeding occurs from early March to mid-May, but even then only a few percent of specimens are in breeding condition. Length of gestation not known. Litter size varies from 1-4 young. Newborns altricial. Reported to have an XO system of sex determination.

American Shrew-moles are described to be "common" throughout their range (Wilson and Ruff, 1999).

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

N. gibbsii do have an effect on controlling bark beetles and other harmful insects in their own habitats. But this is of minimal economic benefit, because most areas where the shrew-mole is found are bad sites for logging or farming (Dalquest, 1942).

Positive Impacts: controls pest population

Comments: Three subspecies (GIBBSII, HYACINTHINUS, and MINOR) were recognized by Hall (1981) and Carraway and Verts (1991).