Geographic Range
Blarina hylophaga
ranges from southern Nebraska and Iowa to southern Texas; east to Missouri and northwestern
Arkansas; Oklahoma; extending into Louisiana.
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
- terrestrial
- Terrestrial Biomes
- forest
- Other Habitat Features
- 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
- 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)
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
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- 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
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-independence
-
provisioning
- female
-
protecting
- female
-
provisioning
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.
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.
- Other Communication Modes
- pheromones
- scent marks
- Perception Channels
- visual
- tactile
- acoustic
- echolocation
- 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
- 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
- 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
- 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
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.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- terrestrial
-
Living on the ground.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- altricial
-
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
- fossorial
-
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- solitary
-
lives alone
- territorial
-
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- pheromones
-
chemicals released into air or water that are detected by and responded to by other animals of the same species
- scent marks
-
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- echolocation
-
The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.
- chemical
-
uses smells or other chemicals to communicate
- biodegradation
-
helps break down and decompose dead plants and/or animals
- soil aeration
-
digs and breaks up soil so air and water can get in
- venomous
-
an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- endothermic
-
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
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.