Insectivores are the descendants of the most primitive
placental mammals
and are the predecessors of all other placental mammals.
Earliest known fossils date back 130 million years ago. Some members of
this order seem to have departed less from the form of the generalized,
primitive mammalian type than have any other recent placentals.
For this and other reasons, certain insectivores are believed to resemble
the basic stock of certain placental lines of descent.
Among the primitive features that many insectivores exhibit are the
structure of the ears, the small brain, primitive teeth, testes that are
usually inside the abdomen rather than in a scrotum, and the joining of the
urinary and reproductive tracts and the intestine into a common channel called
a cloaca. These insect-eating
mammals have long-pointed, flexible snouts with a finely developed sense of
feel (some are carnivorous). Their sight and hearing are poorly developed, and
they all have musk glands, like the weasel family.
They have five clawed toes on all four feet, in contrast to rodents,
like mice, that have only four toes on their forefeet.
These very small, non-hibernating mammals have high metabolic rates and
may consume up to twice their body weight per day. Most insectivores are
ferocious predators with an insatiable appetite, with a constant need to
forage. Shrews have a very short life span and high reproductive rate. Many
exhibit post-partum estrus, with the female becoming pregnant within hours of
giving birth. The pygmy shrew is the smallest mammal in North America.
Worldwide, the Insectivora order includes seven families, 68
genera and 440 species (according to Nowak's Walker's Mammals of the World). Most are
found in the palearctic, Ethiopian, and Oriental regions. More than 70% of the Insectivora are shrews. Other members of this order include hedgehogs (Eurasia and Africa), solenodons
(West Indies), and tenrecs (Madagascar and Africa).
The two largest
families of this order are the only representatives in North America and
in this Appalachian region; the Soricidae (shrews) and the Talpidae (moles). According
to the Checklist of North American Mammals, there are 34 species of shrews and
7 species of moles in North America.
There are eight species in the shrew family and three species
of the mole family in this Appalachian region.
Family
Soricidae - Shrews
ARTICLES
Shrews are small, short-legged, mouse-like animals with long,
pointed noses. Shrews are known
from Eocene fossils in North America (approximately 50 million years ago), but
probably have been around much longer. These
highly energetic mouse-sized mammals have beady eyes with five toes on each
foot (most mice have four toes on the front feet). Shrews have soft fur that
will lie either forward or backward. Teeth of the Soricidae family have chestnut-colored tips.
Often difficult to identify (although long snouts will help
differentiate between shrews and mice). Shrews constitute some of our most
common mammals. However, they
usually inhabit moist areas. This
family includes the smallest terrestrial mammals in the world (the pygmy
white-toothed shrew of Africa, or the Savi's pygmy shrew of the Mediterranean
region, weighing no more than 1/16 ounce). North
America’s pygmy shrew is the second smallest mammal in the world.
Shrews, more primitive than rodents, have a smaller brain, and, like
reptiles, many species, including the northern short-tailed and the least
shrew, have both genital and urinary tracts merge into a
single opening called a cloaca. (As is often the case in nature,
things aren't always simple. The genus Sorex is has two openings,
like most mammals.) Shrews have poorly developed eyesight, but have a
well-developed sense of smell, which it uses in hunt of prey.
Their small size enables them to access food sources unavailable to
most mammals or birds. Shrews are
fairly vocal, with many sounds made that are above the hearing range of
humans. Like whales and bats,
water shrews, wandering shrews and masked shrews utilize high frequency
ultrasonic sounds for hunting, orientation, protection, and communication. The
northern short-tailed shrew has poisonous neurotoxic saliva, similar to cobra
venom that can paralyze or kill a mouse. Shrews are very aggressive and
usually solitary, only meeting to mate. They are very nervous; known to die
from fright from loud noises, even from thunder. Additionally, most species
are known to exhibit post-partum estrus (females coming into heat right after
giving birth)
These primitive mammals essentially do everything extremely
fast. With life spans of normally a year or less, a whole "lifetime"
must be condensed into basically one season. For example, shrews have
extremely high energy/metabolic rates. Under stress, heart rates have been
recorded as high as 1200 beats per minute. Captive short-tailed shrews have
recorded heart rates of 750 at rest with a respiration of 168 breaths per
minute. With the highest surface area relative to body mass of all mammals,
much of the heat they generate metabolically to maintain their body
temperature soon dissipates into the air.
To maintain their metabolic needs, shrews need to eat their approximate
weight every day. Their high metabolic rates require frequent periods of
feeding and short intervals between feedings. To aid in this metabolic
need, some species in the Sorex genus are coprophitic (they eat their feces).
With such a high metabolism and high surface area ratio, they are
unable to hibernate; they would burn up too much calories and lose too much
heat through their skin. To
survive cold periods, they must simply turn up the metabolism and burn more
energy; a costly requirement. Not
able to hibernate, their life cycle is simply a matter of eating and
reproducing before inevitable death.
Most shrews inhabit moist areas. They frequently have markedly restricted habitats, due to their
small size necessitating specific temperature and evaporation
requirements. Due to musk glands, shrews are often killed, but not eaten.
In winter, shrews, like voles, are subnivean, tunneling in snow (mice
generally do not tunnel). Shrew holes, if made in the soil, are 1"
diameter at most. Tracks are often squirrel-like, with the front feet parallel
to the rear feet. Straddle tracks of the long-tailed shrews (Sorex) are only 1"
wide with a tail track often visible, especially in snow. Tracks of the larger
short-tailed shrews (Blarina) are slightly larger. Like field mice, shrews
make runways in moss and vegetation, and make their dens either in their own
dug tunnels or in vacated tunnels of other small rodents.
Scats of shrews are the shape of rice grains, only smaller (1/8 –
3/16” x 1/16”). No sexual
dimorphism exists among the shrews (both males and females are the same size.)
Shrews shed their set of milk teeth very early in life and are seldom
functional. (If lost later in life, they might starve to death
before the new teeth can come in.) In
essence,
one set lasts an entire lifetime, with “old” shrews occasionally found
with their teeth worn down completely.
Shrews are generally extremely solitary with no tolerance of
others of either sex, except for a short breeding period.
They must engage in complex courtship behavior to progress from aversion to
copulation. The least shrew is the exception, having a moderate level of social
ties.
As is everything dealing with shrews, reproduction is a rapid
event. Copulation usually lasts
ten seconds. Gestation is three
weeks. Dispersal of young occurs
in three weeks in most species. This
allows for several broods per season.
This family of 22 genera and 322 species
(Nowak) is found on all continents except Australia and
Antarctica and other smaller land areas.
The
family Soricidae is divided into two subfamilies, with all North American
shrews in the subfamily Soricinae. These
are called the red-toothed shrews because of the red or chestnut pigments on
the tips of their teeth. Twenty
species from five genera are found in North America (Jones).
Nine species of shrews exist in this Appalachian region.
Three genera exist; the long-tailed shrews of the Sorex genus include
seven species, while both the short-tailed shrews of the Blarina genus and the
small-eared shrews of the Crytotis genus have only one representative species
in the Appalachian region. Many
are boreal species, found only in cooler, higher elevations in our study area.
It has been postulated that North American shrew communities will
generally include several shrews and rodents of different sizes, taking
advantage of differing prey and habitats within a given area. For example, the
smoky shrew lives alongside deer mice, red-backed voles, pine voles, woodland
jumping mice, short-tailed shrews and hairy-tailed moles.
Such a community might also consist of three shrews, each feeding on
different sized prey (short-tailed, smoky, and masked shrews feeding on large,
medium and small prey).
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CINEREUS
or MASKED
SHREW
(Sorex cinereus)
(shrew,
ash-colored)
Appalachian
Region Distribution:
A boreal species (northern), found along the Appalachian ridge down to about
Springer Mtn.
Continental Range: Throughout Canada and northern US.
Only one subspecies exists in the Appalachian region.
Abundance: Common, but with large
annual variability. Throughout the Appalachians, especially in moist
environments, it is usually the most common shrew.
Population Density:
W/H reports
densities vary greatly from year to year and from place to place. PA
Mammals reports 1-10/acre.
Size and Molt: Head and body 2 to 2
½ inches; 1/10 - 1/4 oz. This one
does not have a masked face. One of the smallest shrews.
Two molts.
Mammae: Three pair.
Habitat: Found in most variable
habitats of all shrews. Prefers moist, mature, mixed or deciduous forests.
Often found among rocks and logs in moist woods or marshy meadows and
sphagnum bogs. In WVA, it is most common
about beaver dams and alder thickets and in open stands of deciduous and
coniferous forests. In the southern
Appalachians, most common above 3000’ elevation.
Active Period: Active both day and
night (like most shrews), but mainly nocturnal. Consumes up to it’s own body
weight each day (or more - see diet below).
Diet: Insects, earthworms, other
shrews, small mice, snails, slugs, and some vegetable matter. In winter, diet
is mainly insect eggs and pupae, but is known to eat significant quantities of
coniferous tree seeds. Has been reported to eat three times
its weight each day (but its own weight is more reasonable).
Home Range: ¼ acre (1,200 sq. ft.)
to 1 ½ acres.
Social Structure: Often gregarious
(as many shrews may be), with the male often staying with the female during
child-rearing.
Life Cycle: About 3 litters
per year (April through October) with an average of six per litter. Gestation
of 22 days, weaned in three weeks. Young leave the nest at four weeks with
sexual maturity in 2 months, three months, or 5 to 6 months, depending on
publication. (W/H says they don’t breed the summer of their birth, thus, a
life span of 15 months is suggested.) Life
span less than one year.
Nest: 3" spherical
nests of dry leaves or grass in stumps, logs, or under rocks.
Scat: Scats of shrews are the shape
of rice grains, only smaller (1/8 – 3/16” x 1/16”).
Tracks:
Travels and hunts in subterranean tunnels made by itself or other rodents.
Forsyth says the masked shrew does not make it’s own runways.
Straddle tracks are only 1" wide with a tail track often visible,
especially in snow.
Remarks: Heartbeats and respiration
have been recorded at 1200 per minute. Has been reported to eat three times
its weight each day. The young exhibit a "caravaning" habit of
following-the-leader in a single file line, each one with its nose in the fur
of the one in front of it. Is
known to be a good swimmer.
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LONG-TAILED
or
ROCK SHREW (Sorex
dispar) (shrew mouse; dissimilar)
Appalachian
Region Distribution:
Throughout the higher elevations; not in the Shenandoah National Park
Continental Range:
An Appalachian ridge dweller only found from Nova Scotia and southeastern New
Brunswick, through Maine to SW North Carolina and eastern TN.
Two subspecies have been
recognized;
the
separation is about the Maryland border (see remarks).
Abundance: Rare in general, but
locally abundant where it is found.
Population Density: PA Mammals
reports < 2 / acre.
Size and Molt: Head and body 2.4 -
2.9
inches; 1/5 -
1/4 oz. Of medium size, with a much longer tail than the other species. Two
molts.
Mammae: Three pair.
Habitat: Cool, moist upland rocky
habitats of two types: talus slopes, mossy rock piles, or near streams under
rotting logs in deciduous or mixed deciduous/coniferous forests.
Active Period: Active day and
night, year-round.
Diet: Feeds among rocks for
centipedes, insects and spiders.
Home Range: Probably about an acre.
Social Structure: Solitary, and not
territorial.
Life Cycle: One to three litters
per year, with two to six per litter are reported.
Breeding occurs between April through August. Life span of 12 to 18 months.
Nest: Nests in the crevasses
of rocks.
Scat: Scats of shrews are the shape of rice grains, only smaller
(1/8 – 3/16” x 1/16”).
Tracks: Straddle tracks are only 1"
wide with a tail track often visible, especially in snow.
Remarks:
Aka rock shrew. Little is known
about this species due to its subterranean habit.
It has an exceptionally long tail; about half of the total length,
presumably used as a counterbalance. The
long-tailed shrew is significantly smaller in northern latitudes and larger in
the southern part of its range. (The reverse of Bergmann’s Rule.)
In this study area, populations in the southern Appalachians (S. dispar blitchii) are the largest, with decreasing size noted from
Pennsylvania northward (S. dispar dispar).
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MARYLAND
SHREW (Sorex
fontinalis) (shrew mouse; from a spring or fountain)
Appalachian
Region Distribution:
This species occurs in a limited region centering on central Maryland and SE
Pennsylvania. It has also been
found in northern Delaware, NE West Virginia and is probably, but not yet
identified, in northern Virginia. This
is the total continental range of this questionable species (see remarks
below).
Continental
Distribution: It is only found in the Appalachian study area as noted
above.
Abundance: Not known.
Population Density: PA
Mammals reports 1-10/acre
Size and Molt: Head and body
2.1"; 0.08
- 0.16 oz. Two
molts.
Mammae: Three pair.
Habitat: In Pennsylvania,
habitats tend to be moist, including sedge-grass meadows, woodlands, and
hedgerows in early succession. A
collection of 296 by Gordon Kirkland on South Mountain, near Shippensburg, PA
included mature lowland forest, mid-slope oak forest, ridge forest (oak and
blackgum), and oak clearcut 3-4 and 9-10 years old. Many were also
collected in the Cumberland Valley in meadow, hedgerows, and forests.
Active Period: Active year-round.
Diet: Insects, annelids, and other
invertebrates.
Home Range: PA Mammals reports 0.5
to 1.5 acres
Social Structure: Presumed
similar to the masked shrew.
Life Cycle: Two to three
litters of four to six a year. Breeding occurs from late February to
late September in Pennsylvania. Gestation period is 18 days. Lives
up to
18 months.
Nest: Nests are located
below stumps, logs, roots and occasional white-footed mice nests. Nests
are made of grass and leaves and are similar to the masked shrew.
Scat: Scats of shrews are
the shape of rice grains, only smaller (1/8 – 3/16” x 1/16”).
Tracks: Presumed similar to the
masked shrew.
Remarks:
The above information comes from the Mammals
of Pennsylvania (1987) and W/H. Little is known about this species.
The
Maryland shrew was originally described as a distinct species, but in 1911, it
was relegated to a subspecies of the masked shrew, where it remained
until work in the late 1970's and 80's gave it a species status, which it
tenuously still maintains now, amid much technical debate. It may be a hybrid between the masked and southeastern
shrew. The type locality is Cold
Spring Swamp, Prince Georges County, MD.
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SMOKY
SHREW (Sorex
fumeus) (shrew mouse; smoky)
Appalachian
Region Distribution:
Throughout.
Continental Range: Another
mountain boreal species, from southeastern Canada west to Great Lakes and south to the
Smokies and Springer Mtn. Two subspecies
are recognized in
the eastern US with one (S. fumeus fumeus) in this
Appalachian region.
Abundance: Locally abundant (in
favored habitat). Variable in seasons.
Population Density: W/H reports
5-14/ acre,
with extremes reaching 57 per acre. PA Mammals reports 1-6/acre.
Size and Molt: Head and body 2 ½
to 3 inches; 1/5 to 1/3 oz. Two
molts.
Mammae: Three pair.
Habitat: Cool, moist, shady mature
birch or hemlock forests with a deep leaf layer and much fern growth. Roadside
cuts that expose bare rock faces under moss-covered logs and rocks are good
sites.
Active Period: Mainly nocturnal,
but can be active both day and night under the leaf litter, year-round. They
have been trapped at temperatures of -35 degrees.
Diet: Leaf litter inhabitants.
A New York study shows (in preference); insects, earthworms,
centipedes, millipedes, snails, salamanders, and others. Will travel through
tunnels and runways made by moles and voles in search of prey, thus, tend to
eat more worms than most shrews. These have never consumed more than half their weight per day
in captivity.
Home Range: Probably about an acre.
Social Structure: Has been known to
be gregarious in captivity. However, normally considered to be solitary
and highly aggressive towards others.
Life Cycle: Two or three litters of
five to six (2-8) per litter per year, born from April through July. Gestation of 21 days
(Forsyth says two weeks), with female coming into heat right after giving
birth (post-partum estrus). Young leave the nest after one month and become
sexually mature after first winter. Most breeding adults will not survive the
winter (their second winter). Thus,
usually only juveniles are found in winter.
Lifespan, thus, is 14 to 17 months.
Den/Nest: Makes small
baseball-sized, spherical grass/leaf nests 5 to 20 inches below the ground or
in stumps, logs or among rocks.
Scat: Scats of shrews are the shape
of rice grains, only smaller (1/8 – 3/16” x 1/16”).
Tracks:
Often used tunnels made by other small mammals (like moles), especially in the
leaf mold, since their feet
are not adapted for extensive digging (burrows have openings the size of a
dime). Straddle tracks are only 1"
wide with a tail track often visible, especially in snow.
Remarks:
Molts of different colors: spring molt of dull brown; fall molt of dark gray.
Large predator of insects and arthropods.
Known for their echolocation abilities.
Known
for its propensity to forage in leaf litter.
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PYGMY
SHREW (Sorex
hoyi) (shrew mouse; Dr. Philip Hoy)
Appalachian
Region Distribution:
The Appalachian Mountains support disjunct populations from the main Canadian
population that follows the higher elevations to
the Smokies. Until recently, pygmy
shrews were not known in central PA. Also known to exist throughout Virginia and west of the Chesapeake Bay
in Maryland. Although considered a northern species, they have been found in
large numbers in a recently completed eight year study in the Fort
Belvoir, VA area.
Continental Range: The main range of the pygmy shrew stretches from
New England northward throughout Canada, with a disjunct mountain population
in the Appalachians and Rockies. Three
subspecies have been described
in eastern US, with
two
recognized in the
Appalachian region, the border being Maryland.
Abundance:
Most abundant in boreal latitudes. Little
is known since they can avoid being caught by conventional traps; only pitfall
traps seem to work. Assumed rare, but may be more common than known. Fewer
than two dozen have been found in Virginia, Maryland, and North Carolina.
There are only two records in the Smokies.
First found in PA in 1984. Has
been found at all elevations throughout VA. (In fact, the pygmy shrew has the
largest distribution of all shrews in VA.)
Population Density: PA Mammals reports < 1/acre.
W/H says similar to masked shrew (W/H
reports densities vary greatly from year to year and from place to place.)
This species is found at lower densities than other shrews.
Size and Molt: Head and body 1.8 - 2.2 inches; 0.07 - 0.14 oz. By weight,
probably the smallest mammal in the world, weighing about the same as a dime.
The smallest subspecies is the S. hoyi winnemana , whose range covers
most of the southern Appalachians. Its
type locality is the banks of the Potomac River near Stubblefield Falls, 4
miles below Great Falls. It's
size averages just less than two inches (head and body) and weighs two grams,
or somewhat less than a dime. Two
molts.
Mammae: Four pair, as opposed to three pair of other Sorex species.
Habitat: Diverse habitats, but generally well-drained sites, such as
steep rocky slopes (birch-basswood-hemlock woods) with heavy leaf litter,
rotting logs, and rhododendron shrub layer.
Also, grassy areas, such as old field and edge situations, as well as
mixed forests. Wet areas,
including bogs and wet meadows, must be near.
Active Period: Active both day and night, year-round.
Diet: Insectivorous, foraging
through the soil litter layer, preferring grasshoppers and
ants, but often not willing to take on a
worm, due to size. Some herbivorous foods and carrion have been recorded in
pygmy stomachs.
Home Range: ½ acre
Social Structure: Solitary
and highly aggressive towards others.
Life Cycle: Produces one, occasionally two, summer litters per year
with five to eight per litter. Can
give birth any month of the year.
One western Kentucky study found a peak from January to March and a lesser peak
from August to December, with the other sympatric southeastern shrew birthing
in the late spring/summer period (alternating birthing periods). Life
span of 12 to 18 months.
Den/Nests: Dens may be a burrow under a log or in old stumps.
Scat: Scats of shrews are the shape of rice grains, only smaller (1/8
– 3/16” x 1/16”).
Tracks: The pygmy shrew makes very small burrows beneath stumps, fallen
logs and the leaf litter of the forest floor.
The burrows are the size of a large earthworm hole.
The holes are so small (how small are they?), that the holes are not
quite large enough to admit a pencil. Pygmy
shrews have been known to enter dung beetle burrows and eat the contents.
Remarks:
The pygmy shrew approaches the theoretical minimum body size possible since
mathematically, a smaller body size cannot produce as much heat as is lost by
its surface area. (Note, a
recently found fossil was unearthed in some 54 million year old Wyoming
limestone, which is by weight the littlest non-flying mammal ever found, in
fact, smaller than thought possible. The
Batodonoides vanhouteni dwarfs the
previous record holder, the Etruscan shrew, with a total body length of less
than an inch long, and a lower jaw measuring less than a third of an inch
long, with the largest tooth a mere three-hundredths of an inch long.)
Taxonomic
classification of the pygmy shrew is still in question, with placement in
either the genus Sorex, Microsorex, or other subgenus classifications.
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SOUTHEASTERN
SHREW (Sorex
longirostris) (shrew mouse; ?)
Appalachian
Region Distribution:
A southern species, found from central Virginia west into southern West
Virginia and south. Not a common Appalachian inhabitant ; more common in
piedmont and coastal plain. Only
3 records in the Smokies.
Continental Range: Includes
most of the southeastern US. Three subspecies are currently recognized
in eastern US. S longirostris fischeri, found in the Dismal Swamp of VA and NC is designated as
threatened by the USDI. S. longisrostris longirostris is
the only subspecies in the Appalachian region.
Abundance: Uncommon in the
Appalachian Region. With little existing data, it is possible that it may be
somewhat common in the preferred piedmont and coastal plain swamplands.
Population Density: One Alabama
study found a density of 12-18 per acre.
Size and Molt: Head and body 1.9 -
2.7 inches; 1/8 - 1/5 oz. One of the
smallest long-tailed shrews.
Mammae: Three pair.
Habitat: Found in moist or mossy habitats
and early successional fields, most common in the Piedmont and Coastal Plain.
Will also inhabit drier uplands.
Active Period: Day and night,
year-round.
Diet: Most invertebrates, including
spiders, moth larvae, slugs and snails, daddy long-legs, beetles and
centipedes. They are also known
to have munched on some vegetation.
Home Range: Similar to the masked
shrew.
Social Structure: Solitary
and highly aggressive towards others.
Life Cycle: One or two litters of
an average of four per litter per year, born from April to October. Young
often are sexually mature by the end of their first season. Shrews probably
mature, breed and die on an annual turnover basis.
Den/Nest:
Burrows are pencil-sized, normally in mossy areas. Can also be simply
shallow depressions made of
grasses and leaves, usually within or under decaying logs.
Scat: Scats of shrews are the shape
of rice grains, only smaller (1/8 – 3/16” x 1/16”).
Track:
Spends most of their time under the leaf litter of the forest floor and in
subterranean tunnels. Straddle tracks are only 1" wide with a tail track often
visible, especially in snow.
Remarks: First described by John Bachman (of Audubon and Bachman fame)
in 1837, and is also known as Bachman's shrew, who discovered it in 1837. Apparently does not
overlap range of the masked shrew (the two species exhibit contiguous
allopatry, as opposed to sharing common habitat – sympatry).
The short-tailed shrew is sympatric with the pygmy shrew. The boreal masked shrew is normally found above 1500’, while the
southeastern shrew is normally found below 1500”. Due to large range, often brought home by cats, but not
eaten, having strong musk glands, as all shrews.
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COMMON
WATER SHREW (Sorex
palustris) (shrew mouse; marsh)
Appalachian
Region Distribution:
A boreal species, found only in relic populations from the last Ice Age at
high altitude along the Appalachian ridge from southern Pennsylvania south to
the Smokies.
Continental Range:
Throughout Canada, and protruding south through the Rockies and Appalachians. Ten subspecies are recognized in North America.
Four subspecies are recognized in the eastern US, with
two in the
Appalachian region (S. palustris punctulatus; the largest subspecies; whose
type locality is 6 miles NW of Durbin, Shavers Fork of Cheat River, WV
and S. palustris albibarbis in PA and to the north.).
Abundance: Uncommon to rare,
due to restrictive habitat needs. May be locally abundant along high mountain
streams
Population Density: Not
known, but not as uncommon as museum collections may indicate.
Size and Molt: Head and body 3.0 -
3.8 inches; 1/3 -
½ oz. The largest of the long-tailed shrews (Sorex genus) in the
Appalachians. Two molts.
Mammae: Three pair.
Habitat: Always found along banks
of mountain streams of coniferous or mixed coniferous-hardwood forests
(especially sphagnum moss bogs).
It readily takes to water, swimming, diving, floating, running along
the bottom of a pond or creek, and actually running upon the surface of the
water for some distance.
Active Period: Active day and
night, peaking at crepuscular times. Active all year.
Can reduce their metabolic demands in winter allowing them to swim
underwater even under ice.
Diet: Primarily an aquatic hunter,
feeding on small aquatic organisms, larvae and eggs, using its sensitive nose
to feel between and under rocks. Will
eat 5 to 10% of their body weight daily.
Social Structure: Solitary
and highly aggressive towards others.
Life Cycle: Breeds from late winter
well into early summer. Two or three broods per year with an average of five
per brood. Gestation period of 21 days, with female coming into heat right
after giving birth (post-partum estrus). Young reaches sexual maturity in
three months (early season young can breed in first summer, but most wait till
the following spring). Overwintering adults commonly will not survive a second
winter. Life span of 18 months.
Nests: Four-inch wide nest of dried
moss or twigs and leaves has been observed along bankside burrows, in or under
hollow logs, under boulders or roots.
Scat: Scats of shrews are the shape
of rice grains, only smaller (1/8 – 3/16” x 1/16”).
Tracks:
Straddle tracks are only 1" wide with a tail track often visible, especially in
snow.
Remarks: Powerful
swimmers, foraging for aquatic invertebrates. Can dive for lengths up to a
minute. It has a fringe of stiff
hairs that aids in swimming and diving. Trapped
air in the fur minimizes heat loss, but also makes the shrew buoyant, such
that the shrew must paddle vigorously to stay underwater.
Are known to run across the surface of water (documented as much as
five feet); its body supported by the water surface tension and trapped air
bubbles in the stiff hairs of its feet, thus the vernacular "water
walkers". Since the water
shrew spends so much time in the cold water, it is logical that it is the
largest of the Sorex genera (a larger size conserves heat better).
The
U.S. Fish and Wildlife Service is currently considering inclusion of the water
shrew on their list of endangered species.
It is endangered because of siltation and pollution of the streams on
which it depends and numerous other adverse human impacts on its habitat.
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NORTHERN
SHORT-TAILED SHREW
(Blarina brevicauda) (coined word of
unknown origin or meaning; short, tail)
Appalachian Region
Distribution: A widely distributed species, occurring throughout the
Appalachians, south to northern Georgia.
Continental Range: East of Great
Plains, north of Georgia, to southern Canada.
Ten subspecies are recognized in
eastern US (one known only on Martha's Vineyard, one only on Nantucket Island, another
only in the Dismal Swamp. Isolating
mechanisms are the key here.) Basically, only two exist in the Appalachian
region, separated at the VA/NC border. A third subspecies is found
in northeastern PA.
Abundance: Very common
(averaging 25 per acre in good habitat)
Population Density: PA Mammals says
averages from 1 to 10/acre, but quite variable,
depending on habitat quality; up to 80 per acre. W/H reports a range from 1 to
50 per acre. Population crashes are occasional.
Size and Molt: Head and body
3 ½ - 4.2"; ½ - 1 oz. (By weight, the
heaviest shrew/ by length; the second largest in the Appalachian region).
Two molts.
Mammae: Three pair.
Habitat:
Diverse, including moist woods with deep litter, particularly along water
courses, but found throughout region in fields, thickets, and pine woods.
A semi-fossorial creature. In
fact, the most fossorial of the three genera of shrew.
Active Period: Active day and
night; most active at night, year-round. Will limit its activities in winter
to conserve energy. More active
on cloudy days than sunny or rainy days.
Diet: Members of the Blarina
genus often feed on the minute subterranean fungus Endogone
and fungi of related genera (found to constitute 4.9% of total volume of food
in 1973 study). Normally will feed
on prey found in it's burrows. Diverse,
preferring earthworms (eats more earthworms than any other shrew), but also
consuming insects, centipedes, millipedes, spiders, slugs, snails, mice,
frogs, salamanders, minnow, crayfish, and other shrews. Forsyth states that
during some periods, half of the shrew’s diet may consist of meadow voles.
In fact, Forsyth indicates vole and northern short-tailed shrew
populations may fluctuate together in cycles.
Also will eat roots, berries and nuts. They also occasionally cache
food, including beetles and snails. Northern short-tailed shrews eat up to half their
weight or more daily. Winter needs are up
to 43% greater than summer needs. Up
to 90% population loss in winter is possible.
Because of their energy requirements, this shrew is active for short
periods (about 4.5 minutes) separated by periods of inactivity (about 24
minutes).
Home Range: ½ to 2 acres is common,
with
individual range overlap in non-breeding period. Home ranges shift as
prey source diminishes.
Social Structure: Solitary and
territorial, but can
be kept with others of the same species in captivity. Both resident and transient individuals exist. Burrows
are scented by males that will usually keep other males out. NAS says
mates may form unions that are more or less permanent.
Life Cycle: Normally 2 to 3 litters
of an average of 6 or 7 per litter per year. Breeding begins in January or
February and continues through September.
Estrus lasts 2 – 4 days. Gestation
of 21 days, weaned at three weeks, sexually mature attained at about six weeks
in females and 12 weeks in males (Wilson says as early as 47 days for females).
W/H says it is probable that shrews do not breed during the season in
which they are born. Mammals of Virginia says males can breed at seven weeks, and
that some early season born can mate by late summer. Life span of usually less than a year, with captives living
up to 33 months. 20 months.
Den/Nest: Burrows are less than 1" in diameter. Two types made: a
breeding nest (5"- 8" round nests of dried leaves, grasses and often
fur) and a smaller resting nest; both located 6 to 16 inches below the ground
in tunnels or under fallen logs and stumps. Each has several exits. Tunnel systems
include separate cache rooms and latrine rooms.
Tracks: These shrews make runways
in the grass or in leaf litter ½ to ¾" wide. Straddle tracks are only 1"
wide with a tail track often visible, especially in snow. Tunnels and
trails of moles and voles are also used. Piles of snail shells are
notable under logs.
Scat: About one inch long, dark
green and twisted, and deposited in piles near burrow entrances.
Remarks:
Note different genus; these known as short-tailed shrews. There are only three
species in this genus. Members of the Blarina genus are the only mammals in North America to have a
poisonous bite. (The only other mammals equipped with poison glands are the
male duck-billed platypus and the echidna.)
The poison acts on the nerves of its prey, immobilizing it for later
consumption, and can cause pain for several days in humans. Blarina species can use
echolocation to locate burrow entrances, determine whether they were open or
plugged, and distinguish between the different sorts of material plugging
them. (Well-developed olfactory sense probably is key in hunting, not
echolocation.) Known for it’s
aggressive behavior, attacking prey larger than itself. This is possible due
to the poison in the saliva from a submaxillary gland in the mouth, which
enters the prey, slowing the heart rate and breathing, thereby paralyzing it.
The poison is both a neurotoxin and hemotoxin, much like a pit viper. It does not inject the poison, rather, as it chews, the
toxins are soaked into the wound. Thus,
insects can be cached and remain fresh for three to five days. Large insect
eater due to it’s size. A common cat present, but normally not eaten due to
very strong scent gland. This species is well adapted for winter survival,
including a thickening of its winter pelt, ability to cache food, and
restriction to the subnivean environment (under the snow). Actually hunts only
7 to 16 % of the wintertime, allowing the rest of the time for low-energy
consuming activities; such as deep sleeping. Also produces layer of high
energy-storing brown fat on shoulders. Recently, this species has been split
from the southern short-tailed shrew (Blarina
carolinensis), a lower elevation species not found in our Appalachian
region.
OK,
here we go.
While most shrews copulate for only a few seconds, the northern
short-tailed shrew pair remain stuck together for almost half an hour.
It seems the males' erect penis bends in an S-shaped curve; fitting the
females’ vagina. The tip of the
penis has a set of hooked barbs that further secures his hold on her.
Even after dismounting, they remain hooked up. She then may drag him around backward for as long as 25
minutes. Perhaps this prevents
males from being displaced by other males.
Or, perhaps, since this awkward position makes him somewhat vulnerable
to other attacks, only the biggest would subject himself to this compromising
situation.
Why
stop now.
It might be of interest to know that the northern short-tailed shrew’s
penis can only be retracted into its storage sheath with the aid of the mouth.
Noting that mating may occur as often as 20 times, the evolutionary
reason for this cumbersome arrangement is questionable, especially in light of
the danger of certain external extremities getting snagged in the course of
running down burrows. It is
speculated that “some form of female choice of male quality” may be
operating for her benefit (and at his expense).
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LEAST
SHREW (Cryptotis
parva) (hidden, ear; small)
Appalachian
Region Distribution:
A southern species, found throughout the Appalachian region.
Continental Range: East of
Great Plains and NOT in Canada or New England. Extends south to Costa Rica.
Nine North American subspecies recognized, with four eastern subspecies
recognized, and only one – C.
parva parva – found in our
Appalachian
region.
Abundance: Common, with local
populations showing large annual fluctuations.
Population Density:
Nowak reports 12/acre; W/H reports 0.7/acre and 2/acre. PA Mammals
reports 1-2/acre.
Size and Molt: Head and body 2 ¼ -
2 ½"; 1/10 - 2/10
oz. Two molts.
Mammae: Three pair.
Home Range:
W/H and PA Mammals report about 0.5 acres. Other studies report a range between
1 - 3 acres.
Habitat: Unlike most species,
prefers open, dry grassy areas or woods.
Also found in marshy areas (particularly, salt marshes of the coastal
regions).
Active Period: Day and night (more
evening or nocturnal), year-round.
Diet: Insects, spiders, snails,
lepidoptera larvae, small lizards, frogs, earthworms, and carrion. Occasionally feeds on beehive larvae
(thus, the vernacular, bee shrew).
Being more of an open habitat species, more lizards are part of its
diet. Is known to eat its weight
in daily food (although this is thought to be uncommon), and is known to cache
its food.
Social Structure: Species is
gregarious and colonial, with both sexes nesting together and sharing parental
responsibilities. Nests of 31 have been recorded. Two in captivity were
observed burrowing together, with one digging and the other removing dirt from
the burrow and packing the tunnel walls.
Life Cycle: 2 or 3 litters
per year, between March to November is the main period in the Appalachian
study area, with five the average per litter. Up to four or five
litters per year, any month of the year, is likely south of the
Appalachians. Gestation period of 21 days.
Weaned in 21 days, sexually mature in four to five weeks (Mammals of
Virginia says 12 weeks). Exhibits post-partum estrus.
Life span of 18 months.
Den/Nest: Nests are made of grass and
leaves in a globular 4-5" size under logs, stumps, flat rocks, or in
burrows made by others or itself. As
mentioned above, also known as the "bee shrew" because it has been
known to build its nest in beehives.
Scat: Scats of shrews are the shape
of rice grains, only smaller (1/8 – 3/16” x 1/16”).
Tracks:
The runways are about the diameter of a pencil.
They use the runways of mice and rate and the tunnels of moles, or they
construct their own tunnels, which are characteristically wider than high.
Remarks:
18 species constitute this genus. However, this is the only member of its genus north of Mexico.
Cryptotis has only 30 teeth, while those of Sorex and Blarina genera have 32
teeth. Note southern range, dry, sucessional habitat, and gregarious nature that
sets this species apart. The smallest of the three short-tailed shrews
(including the northern and southern short-tailed shrews).
Winter grouping allows for mutual warmth-sharing, allowing a further
northern range. A smaller version of the short-tailed shrew. Takes smaller
prey than short-tailed shrews, foraging both day and night.
Respiration rates of 170 per minute have been recorded.
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Family
Talpidae - Moles
Moles
are larger than shrews, usually with proportionally shorter tails.
They have enlarged forefeet, reduced hind feet and pelvis and short thick fur that
can be rubbed backward or forward (as it moves in its tunnels - this is due to
a flat segment found near the base of each round hair). The eyes are
poorly developed, to the point that they can only detect light from dark.
Hearing is excellent, and the sense of smell is well-developed.
Moles are active both day and night and do not hibernate or aestivate,
but will spend up to ten hours a day sleeping. Like shrews, they have a
voracious appetite, feeding primarily on earthworms and other invertebrates.
Most talpids construct nest and rest chambers.
The
extremely sensitive snout of the mole is unmatched in the animal kingdom.
It is covered with a dense array of nervous receptors connected to
nerve cells supported by a rich supply of blood vessels.
These are organized into structures called Eimer’s organs, most
outrageously developed in the star-nosed mole.
In addition, the snout, paws, tail and back of the head have sensitive
bristles, like cat whiskers, that aid the mole in detecting objects.
Moles
are "fossorial" mammals; they spend practically all their lives
underground. They make two types of tunnels. The pushed-up type we see are
temporary feeding tubes, normally used for only a few weeks. Most food is obtained by prey falling into the
feeding tunnels, rather
than excavating tunnels to find the source.
Tunnels will follow the grubs and worms (shallow in summer, deeper in winter).
The second, deeper ones (down to three feet) are more permanent. These are
used for sleeping, escaping from most predators and avoiding the cold of
winter. Nesting and resting
chambers may be attached to these deep tunnels.
Where food supplies are favorable, generations of moles may inhabit the
same tunnels. Moles will occasionally make vertical shafts to the surface to
disperse excavated soil, especially in heavier, clay soil, often spreading out
the soil to conceal the tunnel. In ideal soils, moles can tunnel at a rate of
over 1 and ½ feet per minute.
Moles
differ from shrews in several characteristics.
Moles have white teeth; not brown-tipped. Moles have enormously enlarged, long-clawed forefeet. The smelling ability of moles is more limited than shrews.
Star-nosed moles can be gregarious, sharing tunnels and paths with other moles (the least
shrew - and the northern short-tailed to a lesser extent - is the only shrew
known to be sociable). Because
of the protection afforded by the fossorial habit, only one annual litter of
two to six offspring occur. Finally, moles have molt lines, appearing as a sharp line of
demarcation between old and new pelage.
Although
the eastern moles are generally solitary, the hairy-tailed and star-nosed mole may live as male-female
pairs during the winter. The
receptive period for females is only once a year, usually in early spring.
Males ensure impregnated females are exclusively mated through the
formation of a plug that forms a sort of chastity belt in the females’
vagina.
From
the 17th through the 19th centuries, moleskins were used
for caps, purses, tobacco pouches, and trimmings for garments.
American imported as many as 4 million moleskins a year from England. The demand for moleskins was so great that its extinction in Germany
was anticipated. In 1959,
approximately one million skins were still trapped in Britain.
Most moleskins now come from Russia.
Moles
are known from the Oligocene in North America (30 million years ago), but
European fossils go back to the Eocene (50 million years ago).
Worldwide,
there are 17 genera and 42 species in this family (Nowak).
There
are seven species from five genera in North America (Jones). Three species are found
in our region.
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HAIRY-TAILED MOLE (Parascalops
breweri) (large, rounded forefeet that act as a shield; Dr. T. M. Brewer -
zoologist)
Appalachian
Region Distribution:
Throughout. From Maryland south, tends to replace the Eastern Mole above 2,000
feet elevation.
Continental Range: In
Appalachians, from New England, west to Great Lakes, south to Springer
Mountain, GA. The type locality is supposedly Martha's Vineyard; a place where the
mole probably does not occur! See
remarks below. No
subspecies are described.
Abundance: Relatively common
above 2,000 feet. Tends not to overlap lower elevation range of the eastern
mole.
The most common mole of the mountains.
Population Density: 1 per acre is
common, up to 11 per acre.
Size and Molt: The smallest of
eastern moles. Head and body 4 ½
to 5 ½"; 1 ½ - 2
oz .
Females generally smaller than males. Two molts.
Mammae: Four pair
Habitat: Various habitats of
mountains, less wet than star-nosed. Prefers
well-drained areas with sandy loam soil and a good cover of vegetation.
Active Period: Day and night,
year-round, although most activity is confined to the deep tunnels during the
colder season. Feeds on the
forest floor mainly at night, thus preyed upon by nocturnal predators.
Diet: Beetle larvae, worms, ants,
ground-dwelling wasps and beetles. Like shrews, (and unlike other moles) will
eat up to three times it’s weight in a single day. (Stokes says one third their body weight.)
Home Range: PA Mammals reports 0.2 acre.
Social Structure:
Solitary lives except when mating time occurs in March/April, when
both sexes will inhabit same tunnel systems.
Females remain near their winter ranges while males leave their winter
ranges to search for mates. Females
remain solitary after mating while males freely associate in spring and share
tunnels in late summer with females and young.
Life Cycle: One litter per
year (sometimes two) with four to six (up to 8) per litter. Mating occurs in late
March and early April. Gestation
period of 4 to 6 weeks. Young are weaned and leave the nest at four weeks. Sexually mature in ten months. Life span of 3 to 5
years.
Nest: Makes winter (8x6" dia,
16" deep), breeding (6" dia, 12" deep), and resting nests
(3", along tunnels). Nests always have several exits. Winters in deeper
tunnels.
Tracks: Mole runs of rounded ridges in dry woodland soils are likely
to have been made by this species. Digs lots of shallow tunnels plus a few to 20" where a
grass and leaf nest is made, having several exits. May use same tunnels for
many years by successive generations. Mole hills exhibited are smaller than
star-nosed mole hills. Hills are more common in fall, as moles dig for winter
tunnels/nests. Tunnels are often interconnected with those made (and
used) by other moles, shrew and mice.
Scat: Cylindrical, tapered at both
ends, about 1" by 1/4". Often
found in piles deposited outside the burrow.
Remarks:
This is the only species in the genus.
Most tails are black, but some have a white tip. Can damage lawns.
Along with the star-nosed mole, has 44 teeth, second only to the
opossum. Can be found with
star-nosed moles, but rarely with eastern moles.
Audubon
and Bachman named this species after Thomas M. Brewer, an “intelligent
naturalist”, who had obtained a collection of small rodentia from New
England. This specific specimen
came to Brewer from Dr. Yale, allegedly from Martha’s Vineyard. (see
Continental Range comments above)
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EASTERN
MOLE (Scalopus
aquaticus) (dig, foot; water dwelling)
Appalachian
Region Distribution:
Throughout.
Continental Range: Eastern
US. The type locality is Philadelphia, PA. Sixteen subspecies are
recognized in North America, with eight subspecies recognized in eastern US.
Two subspecies can be found in the peripheries of the Appalachian
region.
Abundance: Relatively common below
2,000 feet elevation. Apparently uncommon from western and southern mountains
of Appalachian region above 2,000 feet elevation. Tends not to overlap higher
elevation range of hairy-tailed Mole (allopatric).
Population Density: Unknown.
Size and Molt:
Head and
body 4 ½ - 6 ½"; 3 - 5 oz.
Males are larger, on
average, than females. Northern subspecies are larger than southern subspecies.
The eastern mole exhibits the most extensive amount of geographic variation in
size among the moles. Molts twice a year.
Habitat: Everywhere, except very
wet soils. Prefers well-drained
sandy soil. They spend 99% of their time underground.
Active Period: Day and night (peak
time is crepuscular), year-round.
Diet: Voracious eaters of
earthworms, insects, invertebrates, including underground bees and hornets.
Eastern moles will eat an average from 31 to 55% of their body weight
per day.
Home Range: 2 acres for males; 1/2
acre for females. There seems to be a great deal of overlap of male range, but
not female range.
Social Structure: Solitary. Two
placed in captivity have been known to fight to the death.
Each mole defends its own exclusive burrow system, although other
studies show some
tunnels are known to be used by several unrelated moles.
Life Cycle: Eastern moles have only
one litter per year, with only three or four per litter, born in April or May.
Gestation period of four to six weeks. Young are weaned and leave the nest at
four weeks and are sexually mature the following spring. Life span of 3 - 4
years.
Den/Nest: Most talpids construct nest
and rest chambers. The grass and leaf-lined nest is
usually 6-12" underground in a 4 - 8" chamber, with multiple
entrances. Rest nests are normally smaller, but similar in construction.
Some moles used two to seven nests.
Several summer nests may be used, but apparently only one winter nest.
A separate chamber is used as a latrine site.
Tracks: Makes well-known ridges as
well as hills of excavated soil. Foraging tunnels just under
the surface (creating well-known surface mounds) can be dug at ten to twenty
feet per hour. It has been reported that eastern moles can dig up to 100 feet
of tunnel in a day. The longest
recorded tunnel was traced along a fence line for 3,300 feet.
Males construct more extensive tunnel systems than females. Makes two
kinds of burrows: shallow feeding tunnels just under the soil line, with many
used for foraging only once; others used frequently and may be in use for many
years, and deeper
(10" to 24”) tunnels that are more permanent retreats during dry or
cold periods.
Remarks:
This is the only species in the genus. The misnomer species name was given by Linnaeus in 1758 based upon the
description on the original collection label indicating that the specimen was
found (dead) in the water (and its webbed feet).
Highly specialized for a life
underground. These "fossorial" adaptations include broad,
shovel-like front paws and sealed eyelids that can only detect light from
dark. Skin glands on the belly can stain it orange. Has a sensitive tail for
touch. Their reproductive habits would suggest a long life, but data to
support this is lacking. Moles are best controlled by trapping, not poisoning.
It is important to remember that most surface tunnels are ephemeral in use, so
traps must be placed on new tunnels. They have few predators, due to their
isolated lifestyle, and due to their strong musk glands, like shrews, although
one was found in the stomach of a Smokies copperhead.
It is now believed that moles
spend little time in actually digging tunnels.
Noting the energy spent digging tunnels, mole
tunnels are used for up to eight years. This is particularly important in hard, clay soils, which have a high
density of worms and soil animals. In
loose, peaty acidic soils which are poor in food, more time is spent searching
for food by digging.
Basically, when insufficient food is found, more tunnels are dug.
Nowak
suggests that putting a bottle in a surface tunnel, with the opening exposed
to the wind above ground, will drive away moles, due to the sound of the wind.
Chapman and Feldhamer acknowledge this, use of moth balls, and several other
"home remedies" and concludes that results from such efforts are usually
non-evident. Trapping is the most common method of control.
In the 1700's and 1800's
mole pelts were in demand for linings in hats, purses, pockets and other
garments. Color ranges from almost black in the northern range to silver or
gold in the southern races. Have
strong scent glands. Despite its undesirable trait of tunneling in turf, this
insectivore’s diet of injurious insect larvae makes it exceedingly
beneficial.
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STAR-NOSED MOLE (Condylura cristata) (three processes of the tail; crested)
Appalachian
Region Distribution:
Throughout.
Continental Range: From the Great Lakes south along the Appalachian
Mountains to Springer Mountain. Also, a population lives in a different habitat,
along the coastal seaboard into Florida.
Only two subspecies are
recognized in eastern US
and the Appalachian region.
Abundance: Locally abundant,
but not found in all apparently suitable areas.
Population Density: Averages about
0.8 per acre, with 16/acre possible in swamplands.
Size and Molt: No significant
sexual dimorphism, but with larger individuals typical in the northern range.
Head and body 4 to 5"; 1
- 2 ½
oz. Two molts.
Mammae: Four pair
Habitat: Moist, saturated soils
along watercourses.
Active Period: Day and night,
year-round. Has been observed
swimming under ice in winter. Are
found much more often above ground that eastern mole, especially at night.
Home Range: About 1 acre.
Diet: Worms, insects, aquatic prey,
often found by probing the mud along the stream bottom (One New York study –
1931 – found aquatic annelids and aquatic insects to make up 65% of the
total volume of food, with only 9.8% coming from terrestrial annelids. A
Wisconsin study –1966- found earthworms to constitute 84%). Will forage above ground in leaf litter.
In winter, often swims under ice, foraging among the stream bottom.
Due to frozen soil, will forage primarily in the water in winter. Apparently, a deposit of fatty material is stored in the tail during
the winter and spring months, which provides a reservoir of energy during the
breeding period. The highly
sensitive tentacles, supplied with nerves and blood vessels “feel” for
prey. See remarks below.
Social Structure: Often gregarious,
living in small colonies, but this may be more a function of food supply than
social habit. Unlike the other mole
species in this Appalachian study area, the male and female may pair up in the fall and mate in the spring.
Life Cycle: After a
mid-February/March mating, one litter per year (around May) occurs, with an
average of five (up to 7) per litter. Gestation period of 45 days. Independent at three
to four weeks, mature at ten months. Life span of 3 - 4 years.
Den/Nest: 5 - 6" spherical nests
of dried leaves and grasses just below the surface, under logs or roots (but
always above high water). Similar, but smaller, resting nests are also
made. Burrow openings surrounded by excavated soil.
Tracks: Differing from the other
two species of moles, the star-nosed mole alternates between subterranean and
surface runways. Tunnels are
irregular and crooked. Also has
tunnels that open directly under water. Spends
more time on the surface than do the other two species.
Will travel on snow in the winter.
Remarks:
This is the only species of it's genus.
Easy to identify due to the 22 fleshy pink appendages on the nose (containing
highly sensitive tactile organs called Eimer’s organs). They are tactile
receptacles. Evidence has been presented to support the hypothesis that the
star-nosed mole uses an electrical sense to detect prey (presumably in water).
Has 44 teeth, second only to the 50 of the opossum.
This semi-aquatic
mole is an excellent swimmer, often foraging underwater (can stay underwater
up to three minutes). It has been seen swimming under the ice and is
frequently caught in muskrat and minnow traps set in streams and lakes.
Like the hairy-tailed mole, the star-nosed mole pushes
up mounds of soil up to 12 inches in diameter on surface, but it pushes the
soil up from the bottom, so a central hole is never observed. Very hard to
catch by mole traps due to sensitive nose appendages.
Enlargement of the tail with fatty tissues may act as a temporary
reservoir for energy useful during the breeding season.
A
robust population occurs just outside of Richmond, VA.
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