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The Mammals of Texas -
Online Edition Southern Short-tailed Shrew
Habits. Short-tailed shrews occur in forested areas and their associated meadows and openings. Adequate cover and food appear to be more important in determining their presence than type of soil or vegetation. Their burrows usually occupy two zones, one several centimeters below the surface or directly upon it and the other at a deep level, often 40-60 cm below the surface. These two levels are joined at irregular intervals. Frequently, their runs follow just beneath a log, sometimes penetrating and honeycombing the log if it is rotten and easily worked. These creatures are short-legged and slow of gait but they always seem to be in a hurry, running along with their tails elevated at an angle. A slow-walking person can easily overtake them. They are well adapted for digging; the front feet are wide, strong, and slightly larger than the hind feet. Burrowing is accomplished by the combined use of forefeet, head, and nose. Timed individuals were capable of burrowing at the rate of about 30 cm a minute in soft soil. Like the least shrew (Cryptotis), Blarina seem to be more sociable than long-tailed shrews. Several individuals seem to use a common burrow system and seldom do they fight when two or more are placed in a cage. It appears certain that the male and female remain together during the prebreeding season. The food habits of these shrews are strangely unshrewlike in that they consume relatively large quantities of vegetable matter (nuts, berries, and so forth). Analyses of more than 400 stomachs from East Texas revealed the following items (expressed in percentages of occurrence): insects 77.6; annelids, 41.8; vegetable matter, 17.1; centipedes, 7.4; arachnids, 6.1; mollusks (mostly snails), 5.4; vertebrates (mice and salamanders), 5.2; crustacea (mostly sowbugs), 3.7; undetermined matter, 2.4. There is considerable evidence that Blarina stores snails for winter use. An interesting feature of this shrew is the poison produced by the submaxillary glands, which is present in the saliva and may be introduced into wounds made by the teeth. Injections of 6 mg of an extract prepared from the submaxillary gland are strong enough to kill mice but there is little likelihood of the venom having any serious effect on man. The breeding season of Blarina extends from February through September. There appear to be two and possibly three litters of five to seven young produced in this period. The gestation period is probably between 21 and 30 days. The young are pink, blind, and helpless at birth, and they weigh slightly more than 1 g. They are relatively slow in developing; the eyes of young born in captivity were still closed on the 22nd day. The young are born in a special nest of grasses and other dry vegetation under a rotten log or stump or under the ground. In each instance entrance to it is gained by way of an underground tunnel. These nests are much larger than the more commonly found "resting" nests. Records indicate that very few of these shrews attain an age of 2 years. Since the reproductive potential is high in this shrew, one can assume that its natural enemies are many. Known predators include the milk snake, black snake, red-tailed hawk, red-shouldered hawk, sparrow hawk, broadwinged hawk, barn owl, short-eared owl, barred owl, horned owl, long-eared owl, screech owl, fox, weasel, and skunk. Doubtless, others could be added to the list. Photo credit: John L. Tveten. |
Description. A rather robust,
short-legged, short-tailed shrew with long, pointed,
protruding snout; external ears short and nearly
concealed by the soft, dense fur; tail less than half the
length of head and body, usually less than twice as long
as hind foot; upperparts dark slate to sooty black;
underparts paler; tail black above, paler below. Dental
formula: I 4/2, C 1/0, Pm 2/1, M 3/3 X 2 = 32. External
measurements average: total length, 88 mm; tail, 17 mm;
hind foot, 11 mm. Weight, 18-28 g.