Shrew Mole: Neurotrichus Gibbsii

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Image of shrew mole foraging

Description Of The Shrew Mole

The smallest species of the New World Talpidae is the American shrew mole. It has black or blue-black hair and is not as plush as other moles. The forefeet of Shrew-moles are slightly broadened, not webbed and altered for digging only. There are absent external ears. The eyes are reduced considerably, and these animals have a flat, elongated nose. The tail is approximately half as long and reasonably broad as the body.

Learn More: Mole And Shrew Species

Shrew Mole Behavior

Day and night, American shrew-moles are active, and they only sleep one to eight minutes at a time. They remain awake for periods that range from two to eighteen minutes (they don’t hibernate).

Neurotrichus gibbsii, unlike other moles, spends a lot of time on the ground and moves around easily. They are also known to be intentional climbers and, in search of food or a nesting place, can easily climb up low bushes.

Shrew-moles are also excellent swimmers and move through the water using all of their limbs and tail.

Shrew-moles are gregarious and may even travel in groups with more than 11 people. Shrew groups seem to move to an area together, stay there for up to several days, and then move on to another area.

Neurotrichus gibbsii are fossorial, like other moles, and use their tunnels for both motion and hunting. There are two different kinds of tunnels they create. The first is shallow and directly dug under leaf litter. Less common and deeper, but never below 30 cm, is the second.

To create a sleeping chamber, shrew-moles also widen parts of their shallow tunnels. It is possible to find these chambers above ground because they have a vent hole that enables the animal to breathe while sleeping. Because they have open entrances or molehills and are less complex, these tunnels are different than those of other moles. ¹

Reproduction Of American Shrew Moles

Picture of shrew mole

It may have several litters annually, although no litters have been recorded between December and January. Female shrew moles have a litter of one to four offspring. The newborns are approximately 30 millimeters long and less than 1 gram in weight.

In female shrews, until follicles appear in the ovaries, the vagina remains sealed. Males lack a scrotum, but they enlarge the testes and associated glands, which increases their weight. These features make it hard for the sex of shrew-moles to be determined externally.

Shrew Mole Habitat

This species of mole is mostly found in deep humus free soils and deep ravines. In these sites, large-leafed maple, vine maple, red alder, flowering dogwood, various deciduous shrubs, brambles, sword fern, mosses, and skunk cabbage are the dominant vegetation.

In shallow soils, such as those found in burned-over areas, headland Prarie, dry woods, or areas with a stony or rocky substratum, Shrew moles occur less commonly. ²

Range & Distribution Of North American Shrew Mole

The American shrew mole is restricted to Santa Cruz County, California, north through western Oregon and Washington to the western regions of North America. On Destruction Island, Washington, an isolated population occurs.

Shrew-moles are restricted to southwestern British Columbia in Canada and have recently been reported to occur as far north as the region of Squamish. ³

Shrew Mole Diet

The American shrew mole’s diet is made up of small amounts of vegetation and invertebrates, including earthworms (42-49 %) and other insects(12-43%). This species forages in runways of the subsurface, shallow burrows, vegetation litter, and understory. Shrew-moles have been observed climbing in shrubs in search of insects. ⁴

Predators Of The Shrew Mole

Shrews are preyed on by hawks, owls, snakes, and larger mammals. Mammalian predators can kill sometimes, but because of the “sour” odor produced by skin glands, they do not eat this species.

Fish, such as the stomach of a 28 in northern pike taken from Rich Lake, Essex Colorado, contained one adult shrew. Pike may eat short-tailed shrews entering the water, or as more likely, shrews that were swept in by flooding. ⁵

Shrew Mole Classification

The shrews and moles were placed in a mammal order called Insectivora for a long time, containing a number of tiny insectivorous (insect-eating) mammals. Insectivora, however, has been split into several new orders and is no longer an official group.

Today, most mammalogists agree that along with hedgehogs, gymnures, and desmans, true shrews, moles, and solenodons belong in the same order. The name of this new order is Eulipotyphla. This reorganization was prompted by molecular (DNA) evidence, which shows degrees of genetic relationships.

True shrews, moles, and solenodons (but not the hedgehogs, gymnures, and desmans) were considered to be in order Soricomorpha before ordering Eulipotyphla was suggested and accepted. This term may still be used in slightly older references. ⁶

Sources:

Gochis, E. 2002. “Neurotrichus gibbsii” (On-line), Animal Diversity Web. Accessed February 03, 2021 at https://animaldiversity.org/accounts/Neurotrichus_gibbsii/
“Deschutes National Forest – Nature & Science.” United States Department Of Agriculture, USDA Forest Service, www.fs.usda.gov/detail/deschutes/learning/nature-science/?cid=stelprdb5275106. Accessed 3 Feb. 2021.
Campbell, Kevin. “The Mole Tunnel.” The Mole Tunnel, home.cc.umanitoba.ca/%7Ecampbelk/shrewmole.html. Accessed 3 Feb. 2021.
Hoefler, G., and J. Harris. “Shrew-Mole.” Sibr Code, California Department of Fish and Game, 1999, www.sibr.com/mammals/M015.html.
Saunders, D. “Short-Tailed Shrew | Adirondack Ecological Center | SUNY ESF | College of Environmental Science and Forestry.” ESF SUNY College of Environmental Science and Forestry, State University of New York, 1988, www.esf.edu/aec/adks/mammals/shorttailed_shrew.htm.
“Shrews.” MDC Discover Nature, State Of Missouri, nature.mdc.mo.gov/discover-nature/field-guide/shrews. Accessed 3 Feb. 2021.