MAMMALS OF SOUTH
CAROLINA: RODENTS
BIO 402: Field Biology
Presentation by
Dr. Charles Horn
Mammals of South Carolina
This presentation will cover:
• Order Rodentia
What are Rodents?
(aka gnawing mammals)
Taxonomically, characterized by:
• One pair chisel-like incisors on upper &
one pair on lower jaw
• incisors continuously grow, must be worn down
• Canine teeth are missing
Characteristics of Rodents
• Most species with high reproductive rate
(large litter & several litters per year)
• Have induced estrus & ovulation
(due to presence of male)
• Live in essentially every terrestrial environment
(hence of major economic impact)
Rodents are largest group of Mammals
in the Southeast, 36 species. In SC:
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Woodchuck
Chipmunk
Squirrels (4 species)
Beaver
Rats (4 species)
Mice (7 species)
Voles (2 species)
Muskrat
Suborders of Rodents
• Squirrel-like rodents
Infraorbital Canal very small
- woodchuck, chipmunk, squirrels, beaver
• Mouse-like Rodents
Infraorbital Canal somewhat enlarged
- mice, rats, voles, muskrat
• Porcupine-like Rodents
Infraorbital Canal greatly enlarged
- none in South Carolina
What is an Infraorbital Canal?
• An opening in the skull at the base of the
eye socket (orbit) and extends down and
under the eye, and continues forward nearly
to the nose or snout.
• Location of the masseter muscle
From: http://www.uoguelph.ca/~mammals/Lab5/
Woodchuck
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Stocky with short strong legs (burrowers)
Short, flattened tail
Active during day, except at mid-day
One litter a year with 2-6 young
Hibernates in winter, especially to north
Barely gets into northern parts of the state
aka: groundhog, marmot
Eastern Chipmunk
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Reddish-brown with black stripes on back
Well know for pouched cheeks
Non-bushy tails
Dig and live in burrows
Breed twice a year: February & June
4-5 young per litter
• Only live about a year
Gray Squirrel
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Most well known of squirrels
Silver-gray coat with long bushy tail
Active year-round, less so when very cold
Food mostly of various fruits, inc. acorns
Mate in late winter, second litter in July
Beaver
• Typically about 30 pounds, but up to 70 lbs
• Abundant brown fur, flattened black tail
for swimming and noise-maker
• Live in ponds or lakes & build lodges
• Mostly vegetarian, but rarely eats dead fish
• Known as a cornerstone species
cause habitat change with dam-building
Eastern Wood Rat
• aka “pack rat” due to collection of a wide
variety of nonfood items
• Grayish-brown fur, white underside, and
black eyes
• Tail covered with hair
• Vegetarian, leaves, twigs, fruits, and
mushrooms
• Produce 2-3 litters a year
House Mouse
• Well know for invasion into homes
not native, but widespread now!
• Brownish-gray fur with scaly tail
• Large ears
• Mostly nocturnal, looking for grains
• Prolific breeders, up to 13 litter a year
Pine Vole
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Small mouse-like rodent, very short tail
Longer front claws allow for tunnel digging
Mostly eat vegetation and insects
Can be a problem in orchards as vole gnaws
on the tree trunks
• Commonly are colonial and active all year
• Only live 1-2 years, but can produce
up to 6 litters
Picture from: http://www.hiltonpond.org/ThisWeek030222.html
Muskrat
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Size of a rabbit
Aquatic with partially webbed feet
Black, scaly tail is flattened vertically
Common throughout North America
Can build dome-shaped houses like beavers
Active at night, vegetarians; but sometimes
eat fish, crayfish and frogs
• 2-3 litter a year with 4-7 each time
References
Orr, Robert. 1976. Vertebrate Biology. W. B.
Saunders Co.
Numerous web pages including:
Connecticut Department of Environmental Protection