Mammals of Alabama

Shrews, Moles, Desmans, and Relatives

SPECIES ACCOUNTS 175 Shrews, Moles, Desmans, and Relatives Order Soricomorpha Soricomorpha includes 4 families, 45 genera, and 428 species. Members usually have a long and pointed rostrum, a low braincase that does not rise much above the dorsal surface of the rostrum, and eyes that are small relative to the size of the head. Geographic range of the order is worldwide, except Antarctica, the Australian region, and southern South America. Two families (Soricidae, Talpidae) are widely distributed in Alabama . Shrews Family Soricidae Containing 26 genera and 376 species, this family occurs throughout most of North America, all of Europe, Asia, and Africa (including Madagascar ), and northwestern South America. The skull is long and narrow, with no zygomatic arch, postorbital process, or auditory bullae. Rostrum is long and pointed, eyes are small, and ears usually have pinnae. Shrews may occupy tundra, forest, marsh, grassland, and desert habitats. In Alabama , there are 6 species of shrews (northern short-tailed shrew, southern short-tailed shrew, North American least shrew, smoky shrew, American pygmy shrew, southeastern shrew) represented by 3 genera (Blarina, Cryptotis, Sorex). In Alabama and elsewhere, large numbers of shrews die each year in bottles thrown onto roadsides. Shrews enter the bottles in search of food or shelter and frequently cannot escape, especially from bottles with the opening oriented uphill, and they die. Littering is not only dirty and unsightly but can be deadly for some of our native wildlife. 176 SPECIES ACCOUNTS Northern Short-tailed Shrew Blarina brevicauda Identification This relatively large shrew has a short tail and a nearly uniform silvery, slate-gray, or black pelage, sometimes with brownishtipped hairs. Underside is slightly paler than the back. Eyes are minute and external ears are inconspicuous and concealed by the soft pelage. Rostrum is elongate, pointed, and somewhat proboscis-like. This is the largest short-tailed shrew in Alabama. Northern short-tailed shrews can be distinguished from southern short-tailed shrews by the diploid number of chromosomes (48–50 for the northern, 31–46 for the southern). Dental Formula i 4/2, c 1/0, p 2/1, m 3/3, total = 32. Although there is consensus on the total number of teeth, there is disagreement about the number of each kind of tooth. Actually, each upper tooth row has 1 falciform incisor, 5 unicuspids, the fourth premolar, and 3 molars, and each lower tooth row has 1 precumbent incisor, 1 unicuspid, the fourth premolar, and 3 molars. Teeth have dark chestnut-brown tips. Size and Weight Average and range in size of 22 specimens from Alabama : total length, 109 (101–125) mm / 4.4 (4.0–5.0) inches tail length, 24 (20–28) mm / 1.0 (0.8–1.1) inches hind foot length, 14 (13–15) mm / 0.6 (0.5–0.6) inch weight of 13 specimens, 16.3 (11.7–19.7) g / 0.6 (0.4–0.7) ounce There is no significant sexual dimorphism. SHREWS 177 Distribution Northern Alabama. Geographic range of the species is from the Great Plains of southern Canada to central Georgia and from western Nebraska to the Atlantic Ocean. Ecology Northern short-tailed shrews occupy a wide range of habitats including grasslands, agricultural areas, fallow fields, coniferous-deciduous forests, and marshes. Dense understory, deep leaf litter, and favorable temperature and precipitation have been suggested as important components of habitat. Saliva of northern short-tailed shrews is poisonous to humans and other animals. Poison is produced by submaxillary glands and exits through ducts at the base of the lower incisors. When small mammals are bitten, this toxin may cause them to die of respiratory failure and other complications. In addition to incapacitating or killing prey, the toxin may assist in digestion of proteins. Diet includes fungi (Endog­ one), plant materials, larval and adult insects, slugs and snails, earthworms , millipedes, centipedes, spiders, mollusks, and a variety of small vertebrates. Predators include fish (Salvelinus, Lepomis), snakes (Agkistro­ don, Nerodia, Pituophis), owls (Aegolius, Asio, Bubo, Otus, Strix), hawks (Buteo, Circus, Falco), bobcats, coyotes, gray and red foxes, long-tailed weasels, striped skunks, American minks, raccoons, Virginia opossums, and domestic dogs and cats. Behavior Northern short-tailed shrews are generally solitary, with females and young being more sociable than males and older individuals. They are semifossorial, with tunnels usually within the top 10 cm of soil, Distribution of the northern short-tailed shrew in Alabama . 178 SPECIES ACCOUNTS but with some as deep...