Blarina hylophaga

Geographic Range

Blarina hylophaga ranges from southern Nebraska and Iowa to southern Texas; east to Missouri and northwestern Arkansas; Oklahoma; extending into Louisiana.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Blarina hylophaga is found in various habitats. The species prefers the damp soils of oak-hickory and other deciduous forests, grasslands, and the banks of rivers and lakes that allow easy burrowing. However, these shrews avoid standing water. They use the trails and burrows excavated by other small mammals in soft soils. In deciduous forests they most frequently are found near old decaying logs and at the bases of rock outcrops. They may burrow extensively under leaf litter, logs, humus of the forest floor, and deeply into the soil, but ground cover is not required. In addition, they may shelter in logs, stumps, or crevices of building foundations.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

• Other Habitat Features
• riparian riparian

Physical Description

Short-tailed shrews have a head and body length that ranges from 75 to 105 mm, a tail length that is 17 to 30 mm, and a body weight of 15 to 30 grams. Their fur is silvery-gray to black dorsally, and their underside is only slightly paler. The body is robust, with a pointed muzzle that extends beyond the mouth. They have small eyes, ears hidden by the fur, and small front and hind limbs and feet. There is not much sexual dimorphism. Blarina has five unicuspid teeth in the upper jaw. Females have six mammae.

Blarina hylophaga is very similar to Blarina carolinensis . Both are small, slate-gray to brown shrews with short tails and no external ears. However, B. hylophaga has slightly larger cranial measurements, and a noticeably larger fourth premolar. Blarina hylophaga is more gray in color, whereas B. carolinensis is tinged with brown.

In comparison to Blarina brevicauda , B. hylophaga is less robust. In a study done by Russell A. Benedict, the two animals were classified to species by a few characteristics, including hind foot measurement, total length, and weight. Blarina brevicauda were classified as such if having a hind foot measurement greater than or equal to 15.5 mm, a total length greater than 115 mm, and a weight greater than 15 g. On the other hand, B. hylophaga typically weighed less than 20 g, had less than 120 mm in total length, and had a hind foot less than or equal to 15 mm.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Elliot's short-tailed shrews are thought to be polygynandrous, meaning males and females have multiple mates.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Blarina hylophaga is usually solitary, but individuals come together from early spring to early autumn in order to reproduce. The estrous cycle is 2 to 4 days. Gestation averages from 21 to 22 days. Litter size ranges from 4 to 10, with usually 5 or 6 young. The babies are born hairless, pink, and wrinkled. Nests are constructed of leaves, grasses, and plant fibers. They are usually made under logs, in burrows, or even rarely, on top of the ground. Females produce 2 to 3 litters per year.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

Parental care is provided by the females. The young of B. hylophaga leave the nest at 18 to 20 days and are weaned a few days after. Females attain sexual maturity at 6 weeks of age, and males at 12 weeks of age. It is possible for a female shrew born in early spring to breed by late summer or autumn of the same year. Males, most often, do not breed until the spring after their birth.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

Few wild Blarina individuals survive more than a year. However, captive individuals have survived to 33 months.

Behavior

Blarina hylophaga does not hibernate, but is active throughout the year. These shrews can be seen by day or night. They are a solitary and territorial species, only coming together to breed. Residents of a territory fight off intruders. Individuals mark their ranges with scent. The skin contains glands, especially on the flanks and anal region in both sexes, that secrete odors repugnant to predators. Their odor may also act as a chemical signal to attract or deter other shrews. As a consequence, you will smell this odor especially during breeding season. Blarina are effective climbers. And although they do not hibernate, in the winter they store reserves of food.

• Key Behaviors
• terricolous
• fossorial fossorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

The size of the home range of these shrews is not available.

Communication and Perception

Elliot's short-tailed shrews use scent for communication of reproductive and territorial information. It is likey that tactile cues are important during mating and between a mother and her offspring. They also use echolocation to help navigate underground and to hunt.

• Communication Channels
• tactile tactile
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• echolocation echolocation
• chemical chemical

Food Habits

Shrews feed primarily on insects. Many other invertebrates, small vertebrates, and some vegetable material, particulary seeds, are also eaten. Insects, arthropods, and earthworms are more frequently eaten. They capture food by searching ground litter, digging superficial burrows in the ground, and using echolocation by high-pitched calls. Blarina hylophaga has specialized teeth from which submaxillary glands secrete poison. This poison immobilizes small animals, making it possible for shrews to kill prey larger than themselves, such as mice, fast and efficiently.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• mammals
• amphibians
• insects
• terrestrial non-insect arthropods
• terrestrial worms

• Plant Foods
• seeds, grains, and nuts

Predation

The skin of B. hylophaga contains glands that secrete odors repugnant to predators. Carnivorous mammals often capture B. hylophaga , but seldom eat them due to these foul-smelling skin glands. Predators include owls , hawks , snakes , and domestic cats .

The skin of Elliot's short-tailed shrews contains glands that secrete odors repugnant to predators. Carnivorous mammals often capture these shrews but seldom eat them due to these foul-smelling skin glands. Predators include owls , hawks , snakes , and domestic cats .

Ecosystem Roles

Blarina are the most fossorial of American shrews, aiding in soil aeration. They use surface and subsurface runways and burrows of small mammals. They also use leaf litter and decomposing trees to burrow and nest. Blarina serves an important role in controlling the population size of larch sawflies and other destructive insects.

• Ecosystem Impact
• biodegradation biodegradation
• soil aeration soil aeration

Economic Importance for Humans: Positive

Blarina hylophaga serves as a check on larch sawflies and other destructive insects.

• Positive Impacts
• controls pest population

Economic Importance for Humans: Negative

The venomous saliva of B. hylophaga has negative effects on humans when they are bitten, although the venom is not life-threatening. This shrew may also be a nuisance when sheltering in crevices of building foundations, especially because they produce a foul smell.

• Negative Impacts
• injures humans
  • bites or stings
  • venomous venomous
• household pest

Conservation Status

Blarina hylophaga has a Global Heritage and National Heritage status rank of G5 and N5 respectively by the U.S. ESA. Both these rankings describe the species' status as secure, meaning individuals are common, abundant, and widespread in its range. Blarina species have been wiped out by human development and habitat loss, as well as predation by domestic cats. The subspecies B. hylophaga plumbea is known by 7 specimens on the Texas coast at the Aransas Wildlife Refuge, where small groups of B. hylophaga have been recently discovered.

Other Comments

Blarina are effective climbers. One B. brevicauda individual was documented to have climbed 1.9 m up a tree.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Tanya Dewey (editor), University of Michigan-Ann Arbor, George Hammond (editor), Animal Diversity Web Staff, Gail McCormick (editor), Animal Diversity Web Staff.

Nancy Shefferly (editor), Animal Diversity Web Staff.

Dana Begnoche (author), University of Michigan-Ann Arbor, Bret Weinstein (editor), University of Michigan-Ann Arbor.

References

Benedict, R.A., Feb. 1999. Characteristics of a hybrid zone between two species of short-tailed shrew (Blarina). Journal of Mammology , 80: 135-141.

Braun, J.K., G., Nye, R., Stafira, J.. 2001. "Sam Noble Oklahoma Museum of Natural History" (On-line). Accessed September 30, 2001 at www.omnh.ou.edu/mammalkey/ .

Davis, W., D. Schmidly. 1994. "The Mammals of Texas {Online Edition}" (On-line). Accessed September 30, 2001 at www.nsrl.ttu.edu/tmot1/ .

George, S. 1999. Elliot's short-tailed shrew, Blarina hylophaga. Pp. 51-52 in The Smithsonian Book of North American Mammals . Washington, DC: Smithsonian Institution Press.

Hutterer, R. 1993. "Smithsonian National Museum of Natural History Mammal Species of the World" (On-line). Accessed October 7, 2001 at nmnhwww.si.edu/cgi-bin/wdb/msw .

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition . Baltimore and London: The Johns Hopkins University Press.

The University of Kansas, 2001. "University of Kansas Key to Mammal Species in Kansas" (On-line). Accessed September 30, 2001 at www.ukans.edu/~mammals/ .

Vaughn, T.A., R., Czaplewski, N.J.. 2000. Mammology . New York: Saunder's College Publishing.