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

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) Characteristics of Rodents

Rodents are largest group of Mammals in the Southeast, 36 species. In SC: 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:

Woodchuck 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 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 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 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:

Muskrat 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 Vertebrate Biology. W. B. Saunders Co. Numerous web pages including: Connecticut Department of Environmental Protection