Eastern Musk Turtle
Sternotherus odoratus

Common Name:

Eastern Musk Turtle

Scientific Name:

Sternotherus odoratus

Etymology:

Genus:

Sternotherus is derived from the Greek word sternon which means "sternum" and therion which means "wild animal".

Species:

odoratus is derived from the Latin word odoratus meaning "to have an odor".

Average Length:

2 - 4.5 in. (5.1 - 11.5 cm)

Virginia Record Length:

5 in. (12.9 cm)

Record length:

5.4 in. (13.7 cm)

PHYSICAL DESCRIPTION: This turtle is small, with an oval, elongated carapace that can have a length anywhere between 52-129mm. Max length for a Virginia specimen is 129mm. The shell is domed and is usually darkly colored (brown/black) with irregular dark patterning. This patterning may not be apparent in older turtles. Scutes are as follows: 11 marginals on each side, 4 pleurals on each side, and 5 vertebrals *10760*. The plastron is relatively small and has a single inconspicuous and poorly developed hinge situated between the second and third pairs of scutes. The hinge is not developed in the young, and the pectoral scales are quadrangular. The 11 scutes of the plastron are reduced in size and the skin shows in between scutes. Plastral length ranges from 37-100mm (about 71-79% of the carapacial length) with a max length in Virginia of 129mm. The plastron is usually brown to yellowish with the skin between the scutes white to yellowish *10760,11624*. The skin is dark with some variable light markings except for to distinct yellow/white stripes on either side of the head, one above and one below the eye. There are 2 pair of barbels on both the chin and throat *1038,10760*. Adults can weigh between 23-318g with 318 being the maximum known weight in VA. Males and females do not differ greatly and size. Males have a thicker tail with a small barb on the end and the anal opening extends past the edge of the carapace. They will also have more skin exposed in between the plastral scutes and will have patches of raised scales behind the knee. These differences do not develop till the third or fourth year *1038,10760*.

JUVENILES: Hatchlings are patterned as adults; they have three keels on the carapace and the plastron's hinge has not developed. They have carapace length at hatching of 20-25mm, plastral length of 15-19mm and weigh 2-3g *10760*.

CONFUSING SPECIES: Could be confused with Sternotherus minor, Kinosternon baurii, and K. subrubrum. S. minor has yellow and black stripes on the neck and only one pair of barbels on the chin. K. baurii and K. subrubrum both have two plastral hinges and no exposed skin in between plastral scutes.

REPRODUCTION: The eggs are elliptical and vary in size and shape averaging 3/4 inch by 1 inch, surrounded by a thick, brittle shell resistant to desiccation *1008*. The eggs have a white shell. Active spermatozoa are present from September to May, and spermatozoa can survive in females for weeks and maybe even months *1038*. The breeding season occurs in late May *1008*. Research in South Carolina and Tennessee found fall to be the major period of mating and another minor peak in the spring *10760*. The eggs remain in the oviduct for about 1 month while albumen and shell are secreted. Incubation is from 60-90 days (depending on temperature) *1008*. The males are sexually mature in the third or fourth year, and the females mature in 9-11 years *1038*. During the last part of of June, the females leave the shallows to lay eggs at any hour. After laying the female returns to the water *1008*. The male takes an aggressive role following the female and copulating upon capture *1038*. There are 3 to 5 eggs per clutch *1008*. Female lays 1-2 clutches per-year and the clutch sizes in Virginia have varied from 1 to 9 eggs *10760*.

BEHAVIOR: This species is a weak swimmer often seen crawling on mud in quiet water. They seldom leave the water except to lay eggs, and will desert water that has become brackish by man's interference. They cannot tolerate anything but freshwater. They have a bad temperament, and will hiss, open the mouth threateningly and often bite *1038*. There is no uniformity to the nest site, which can be anywhere from covered to deposited on the surface. Many uncovered eggs contain viable embryos *1008*. Hatchlings make their way unassisted to the water right away *1008*. This species hibernates in large groups buried in mud bottoms of ponds or streams, but sometimes hibernate alone. They usually emerge about the middle of April *1008*. They will hibernate buried 12 inches or so in the mud bottom under the water in recesses in banks, or in muskrat dens or lodges *2988,10760*. This species does not normally bask *1038*, But rarely does rest in shallow water with the top of the carapace exposed to sunlight. They may bask on banks or in old fallen trees *2988*. Males are aggressive during mating, he chases female, nudges her shell, bites at her head and grasps edge of shell when mounted, this style is considered a forced insemination *10760*. When the turtle is disturbed it releases a drop of fluid from each of the four glands located under the carapace anterior and posterior to the bridge, the fluid has a musk odor *10760*. They are omnivorous and mostly forage along the muddy bottoms of ponds and lakes for insects, small mollusks (snails), crayfish, algae, and various seeds.

ORIGIN: This species is native *10760*.

POPULATION PARAMETERS: The sex ratio is 1:2.3 *2988*. In a Henrico population Eastern Musk Turtles in one lake were found at a density of 188/hectare. This population had an equal sex ratio and was growing at 3.2% per year. There was little dispersal. Other populations have not been found to be this dense and there is considerable variation among populations. Musk turtle live between 15-19 years in the wild *10760*.

AQUATIC/TERRESTRIAL ASSOCIATIONS: Predators on eggs include skunks, raccoons, herons and crows. Predators of juveniles include largemouth bass, bullfrogs and cottonmouths. Predators of adults are muskrats *2988*.

References for Life History

  • 1008 - Barbour, R.W., 1971, Amphibians and reptiles of Kentucky, 334 pgs., Univ. of Kentucky Press, Lexington, KY
  • 1038 - Pope, C.H., 1939, Turtles of the United States and Canada, 343 pgs., Alfred A. Knopf, Inc., New York, NY
  • 2988 - Ernst, C.H., R.W. Barbour, 1972, Turtles of the United States, 347 pgs., Univ. Press of Kentucky, Lexington
  • 10760 - Mitchell, J. C., 1994, The Reptiles of Virginia, 352 pgs., Smithsonian Institution Press, Washington, DC
  • 11624 - Mitchell, J. C., 2001, Personal Communication, Expert review for GAP Analysis Project, Mitchell Ecological Research LLC

Photos:

*Click on a thumbnail for a larger version.


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FROGS

Virginia is home to 28 species of frogs and toads.

SALAMANDERS

We have a large diversity of salamanders consisting of 56 different species and subspecies.

LIZARDS

Virginia is home to 9 native lizard species and two introduced species, the Mediterranean Gecko and the Italian Wall Lizard.

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The Commonwealth is home to 34 species and subspecies of snake. Only 3 species are venomous.

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Virginia has 25 species and subspecies of turtle. Five of these species are sea turtle.