Family: Soricidae, Shrews view all from this family
Description The largest shrew in North America. Solid gray above and below. Short tail. L 3 3/4–5" (96–127 mm); T 3/4–1" (20–25 mm); HF 1/2– 3/4" (12–20 mm); Wt 1/2–1 oz (14–29 g).
Warning The shrews of the genus Blarina are unique among mammals in producing poison in their salivary glands. The saliva is not dangerous to humans, but a bite may swell and be painful for several days.
Similar Species Southern Short-tailed Shrew is smaller. Least Shrew is grayish brown or brownish.
Breeding 4–8 young born from spring through fall, sometimes thoughout the year. Gestation 17–21 days.
Habitat In the north, a variety of habitats; in warmer, drier parts of range, more confined to woods and wet areas.
Range Southeastern Canada and ne U.S. south to Nebraska, Missouri, Kentucky, and in mountains to Alabama. Isolated populations in ne North Carolina and wc Florida.
Discussion The poison in this shrew's saliva is apparently used to paralyze prey, such as snails and earthworms, which can then be stored for future use. A voracious eater, consuming from half to more than its own weight per day (in captivity), the Northern Short-tailed Shrew also feeds on centipedes, beetles, and other invertebrates, and quantities of the tiny subterranean fungus Endogone. It sometimes even feeds on mice, particularly nest young when mouse populations are very high, and it will occasionally eat smaller shrews. Using its sturdy snout as well as its powerful forefeet, this species excavates underground runways, which it patrols for prey mainly in early morning and late afternoon. Males mark their burrows with secretions from well-developed glands on the hips and belly; other males looking for mates will not enter burrows so marked. This system of territorial marking helps prevent meetings between individuals of this species, which often result in fierce combat. However, fights usually end when one shrew assumes the submissive posture of lying on its back, allowing the other to flee. Mates, however, may form unions that are more or less permanent. The Northern Short-tailed and Southern Short-tailed shrews were previously considered the same species, but the two are now recognized as separate since they remain distinct where they occur together in Nebraska. The Northern is one of the most common North American mammals.
