By Brian J. MacGowan
and Harmon P. Weeks, Jr.
People can be taken aback by the sight of squirrels missing hair.
This past winter, sightings of partially furred squirrels seemed
to be more frequent than usual. Like many wildlife issues, the
cause of hair loss in squirrels is not easy to answer and often
results in more questions than answers. In most situations, hair
loss does not impact populations of squirrels. However, individuals
may be impacted during winter.
Most people assume,
often incorrectly, that hair loss in squirrels is the result
of mange, a disease caused by microscopic mites that
burrow into the skin and are unseen by the naked eye. Hair loss
attributed to the squirrel mange mite, Notoedres douglasi, has
been reported in both fox and gray squirrels. Notoedric mange is
different from sarcoptic mange. The latter, caused by the mite
Sarcoptes scabiei, occurs primarily among red foxes and coyotes.
Questions exist regarding the host specificity of mange mites.
In light of new evidence, some pathologists now believe that sarcoptic
mange mites are not as host-specific as previously thought. However,
notoedric mange mites appear to be more host-specific, and don’t
colonize non-hosts (like humans), although a few bites may occur.
Transmission of notoedric manage to species other than squirrels
has not been documented, including to canine and feline pets.
Symptoms of notoedric
mange in squirrels includes loss of hair and dry, thickened and
dark skin. Crust does not form on the skin
in notoedric mange in squirrels like it does in sarcoptic mange
in red fox. Mange is most commonly spread by direct animal to
animal contact. Treatment of adult squirrels with mange is generally
recommended because reinfection from their nest is likely. An
adult squirrel can survive mange if in otherwise good condition.
mange can be fatal to squirrels as a result of exposure during
the winter, full recovery is often observed in squirrels.
While mange is commonly
presumed to be the culprit, most hair loss in squirrels is caused
by a variety of superficial fungal
generally termed dermatophytoses. Hair from squirrels infected
with fungal agents is typically broken off at the skin, leaving
a fine stubble of short hairs. Damp weather is thought to play
a role in some fungal outbreaks. This past autumn was relatively
wet for Indiana standards and may have contributed to the apparent
observed increase of hair loss in squirrels this winter. Most
animals will eventually gain an immune response and recover
from the fungal
infection without any apparent consequences.
Some hair loss in gray
and flying squirrels is thought to be an inherited condition
where the hair follicles are non-functional
or absent, although studies confirming this have not
been done. These squirrels have normal, but bare skin.
The next time you see
a squirrel with hair loss, don’t become
alarmed. In most cases, the hair will return with
no apparent ill affects to the squirrel, other than perhaps some
and name calling among his squirrel friends.
For more information
about squirrel hair loss or other wildlife diseases, check out
W. R., and V. F. Nettles. 1997. Field Manual of Wildlife Diseases
in the Southeastern United States, 2nd edition
- Southeastern Cooperative
Wildlife Disease Study, University of Georgia, Athens,
GA, (706) 542-1741, http://www.uga.edu/scwds/
Animal Disease Diagnostic Laboratory http://www.addl.purdue.edu/
- Indiana Wildlife Conflicts Information Hotline http://www.entm.purdue.edu/wildlife/wild.htm
- Michigan DNR Wildlife Disease Manual www.michigan.gov/dnr/0,1607,7-153-10370_12150_12220---,00.html
in Your Yard
Brian MacGowan, Extension Wildlife Specialist, Department
of Forestry and Natural Resources, Purdue University
There are 18 species and subspecies of turtles in Indiana, and
about 260 species worldwide. Turtles represent the oldest and most
primitive living reptiles. Reptiles are distinct from amphibians
in that they have scaly skin; eggs with a tough, calcareous (calcium-containing)
shell, a yolk sac, and an embryonic membrane; clawed toes; a three-chambered
heart (four in crocodilians); and a male copulatory organ (except
in the tuatara).
The most obvious and distinctive feature of turtles is their shell.
Relatively unchanged over the past 225 million years, turtle shells
are made up of two parts. Many bones covered with skin that is
modified into horny scutes (except for softshelled turtles) form
each part. The domed top is called the carapace while the flattened
bottom is called the plastron. The carapace and plastron are connected
on each side by bone or cartilage.
Where do turtles go during the winter?
In colder climates, most turtles hibernate buried in the mud on
the bottom of waterways, yet others will burrow underground in
uplands. A combination of factors allows turtles hibernating underwater
to essentially hold their breath for up to four months without
drowning. Colder water holds a higher amount of dissolved oxygen
than warmer water. Furthermore, turtles need far less oxygen and
energy when they are near freezing. Many turtles can also supplement
their oxygen supply by gas exchange through highly vascularized
regions of their neck and specialized sacs around their vent.
I used to see more turtles; where did they go?
Experts agree that populations of many species of turtles have
declined in Indiana and across the Midwest. Habitat loss and inadequate
recruitment of new turtles into existing populations are likely
factors. Eggs and juveniles are susceptible to predation by foxes,
skunks, and raccoons. In specific cases, predation can approach
or even reach 100%.
Turtles are not capable of rapid turnover like deer. Some turtle
species do not reach sexual maturity until they are 15-20 years
old. This makes populations particularly sensitive to the loss
of reproductive adults, as by collection for pets and death on
roadways. For many species of turtles, basic information about
ecology and population biology is still unknown or poorly understood.
This autumn, the state of Indiana passed new regulations for Eastern
Box Turtles. It is now prohibited to collect Eastern Box Turtles
from the wild. You are required to obtain a special purpose turtle
possession permit to keep an Eastern Box Turtle as a pet.
While new environmental regulations may not be welcomed by all,
recent research has determined that many populations of Eastern
Box Turtles are in trouble. Contributing factors include:
- High adult population
density is critical for successful reproduction since the
males must literally see and recognize potential mates.
abundant predators including raccoon, red fox, and skunk.
Box Turtles can live beyond 60 years. Many people who collect
them turn the turtles loose when they are no longer wanted.
Displaced box turtles have difficulty surviving and may pose disease
risks to free-ranging turtles.
The Eastern Box Turtle is a small terrestrial species that possesses
a horny beak, stout legs, a high domelike carapace that is slightly
keeled, and a hinged plastron that allows total shell closure.
The coloration of the carapace varies, but is usually brownish
or black with varying amounts of yellow or orange radiating patterns
of lines, spots, or blotches. The edges of the carapace flare outwards.
Body coloration is also variable, but is usually brown with some
yellow, orange, or white spots or streaks. In very young Eastern
Box Turtles, the carapace is predominately dark with a yellow rim
and spots on the vertebral keel and center of each scute. In many
individuals, the color expands as the turtle ages. The plastron
of young turtles is yellow with a central dark blotch. The sexes
are similar in size. The carapace of an average-sized adult is
about 5 to 6 inches (12 to 16 cm). The iris of most adult males
is red, the rear lobe of their plastron is concave, and the hindclaws
are longer and more curved. Females have a brown iris (Fig. 17),
a flat or slightly convex plastron (Fig. 18), short and straighter
hindclaws, and a relatively more domed carapace.
Distribution and Status
The range of the Eastern Box Turtle extends from southern Maine
to Michigan, and south to Florida and eastern Texas. It is declining
in the Great Lakes region, but populations can be locally common
in areas not bisected by heavily traveled roads. They are a species
of Special Interest in Ohio, and of Special Concern in Michigan.
The Eastern Box Turtle is found throughout Indiana, but is much
more common in the southern half of the state. Casual collection,
collection for the foreign pet trade, and roadway kills (Fig. 19)
are all significant threats to this species. In some areas, nest
predation by raccoon, foxes, skunks, crows, and snakes can be significant
natural mortality factors. Eastern Box Turtles cannot be sold or
purchased in Indiana. Moreover, as of October 23, 2004, no Eastern
Box Turtles may be taken from the wild in Indiana.
Ecology and Behavior
The Eastern Box Turtle is found almost exclusively on land, predominately
in moderate to well-drained woodlands. They can also be found in
thickets, fields, pastures, vegetated dunes, marshes, and on the
edges of bogs. Access to water is still important for the Eastern
Box Turtle. Individuals will sometimes soak around the edges of
small streams or ponds on the hottest days. They are primarily
active during daylight hours although nesting females are active
at night. Fruits, berries, fungi, snails, worms, slugs, and insects
are all readily consumed by this species. They will also eat carrion
on occasion. Eastern Box Turtles reach sexual maturity at seven
to ten years of age and reach full size around 20 years. Some evidence
suggests that individuals may live up to at least 120 years of
To learn more about
all 18 species of turtles native to Indiana, visit www.agriculture.purdue.edu/fnr/wildlife/turtles/index.htm for
information how to order Turtles of Indiana.
Working for YOU!, http://news.uns.purdue.edu/UNS/html4ever/031125.Swihart.squirrels.html