Northern Short Tailed Shrew

The northern short-tailed shrew (Blarina brevicauda) ranges throughout the north- central and northeastern United States and into southern Canada (George et al., 1986). It eats insects, worms, snails, and other invertebrates and also may eat mice, voles, frogs, and other vertebrates (Robinson and Brodie, 1982). Because they prey on other vertebrates, shrews can concentrate DDT (and presumably other bioaccumulative chemicals) to levels 10 times higher than either Peromyscus and Clethrionomys (Dimond and Sherburne, 1969). Shrews are an important component of the diet of many owls (Palmer and Fowler, 1975; Burt and Grossenheider, 1980) and are also prey for other raptors, fox, weasels, and other carnivorous mammals (Buckner, 1966). Short-tailed shrews are 8 to 10 cm in length with a 1.9 to 3.0 cm tail (Burt and Grossenheider, 1980). The short-tailed shrew is the largest member of the genus, with some weighing over 22 g (George et al., 1986; see table). Some studies have found little or no sexual dimorphism in size (Choate, 1972), while other reports show that males are slightly larger than females (George et al., 1986; Guilday, 1957). Short-tailed shrews are active for about 16 percent of each 24-hour period (Martinsen, 1969). They inhabit a wide variety of habitats and are common in areas with abundant vegetative cover (Miller and Getz, 1977), and need cool, moist habitats because of their high metabolic and water-loss rates (Randolph, 1973). The short-tailed shrew is primarily carnivorous. Stomach analyses indicate that insects, earthworms, slugs, and snails can make up most of the shrew's food, while plants, fungi, millipedes, centipedes, arachnids, and small mammals also are consumed (Hamilton, 1941; Whitaker and Ferraro, 1963). Small mammals are consumed more when invertebrates are less available (Allen, 1938; Platt and Blakeley, 1973, cited in George et al., 1986). Shrews are able to prey on small vertebrates because they produce a poison secretion in their salivary glands that is transmitted during biting (Pearson, 1942, cited in Eadie, 1952). The short-tailed shrew stores food, especially in the autumn and winter (Hamilton, 1930; Martin, 1984).