Common Musk Turtle

Sternotherus odoratus is a species of small turtle in the family Kinosternidae. The species is native to southeastern Canada and much of the Eastern United States. It is also known commonly as the common musk turtle, eastern musk turtle, or stinkpot due to its ability to release a foul musky odor from scent glands on the edge of its shell, possibly to deter predation. This turtle is grouped in the same family as mud turtles. The stinkpot is a small black, grey or brown turtle with a highly domed shell. It grows to a straight carapace length of approximately 5.1–14 cm (2.0–5.5 in) and averages in weight at 603 g (1.329 lb). It has a long neck and rather short legs. The yellow lines on the neck are a good field marker, and often can be seen from above in swimming turtles. Males can usually be distinguished from females by their significantly longer tails and by the spike that protrudes at the end of the tail. The anal vent on the underside of the tail extends out beyond the plastron on males. Females are also typically larger than males. The head is vaguely triangular in shape, with a pointed snout and sharp beak, and yellow-green striping from the tip of the nose to the neck. Barbels are present on the chin and the throat. The plastron is relatively small, offering little protection for the legs, and has only one transverse, anterior hinge. Algae often grow on their carapaces. Their tiny tongues are covered in bud-like papillae that allow them to respire underwater. The eastern musk turtle is almost entirely aquatic, spending the vast majority of its time in shallow, heavily vegetated waters of slow moving creeks, or in ponds. It typically only ventures onto land when the female lays eggs, or in some cases, to bask. It can climb sloping, partially submerged tree trunks or branches to as high as 2 m (6.6 ft) above the water surface, and has been known to drop into boats or canoes passing underneath. It is a poor swimmer and can most often be found walking along the bottom of its native habitats, which include swamps, marshes, ephemeral pools, and large rivers and lakes. Its defense mechanism is to excrete a musk scent from a small gland in its underside, hence the name musk turtle. This is used to scare away predators and natural enemies. The stinkpot is carnivorous, consuming a wide variety of aquatic invertebrates including crayfish, freshwater clams, snails, aquatic larvae, tadpoles and various insects. It will also eat fish and carrion. A hatchling's diet is much more carnivorous than an adult's, and may slowly acquire a taste for aquatic plants as the turtle matures. A wild common musk turtle often will not hesitate to bite if harassed. Because its neck can extend as far as its hind feet, caution is required when handling one. S. odoratus turtle is found in a variety of wetland habitats and littoral zones, particularly shallow watercourses with a slow current and muddy bottom. Although it is more aquatic than some turtles, it is also capable of climbing, and may be seen basking on fallen trees and woody debris. Fallen trees and coarse woody debris are known to be important components of wetland habitat, and may be particularly beneficial to basking turtles. Like all turtles, the stinkpot must nest on land, and shoreline real estate development is detrimental. S. odoratus is also commonly found on roads during the nesting season, having fallen victim to road mortality, particularly after heavy rainfall. It hibernates buried in the mud under logs, or in muskrat lodges. Breeding of the eastern musk turtle occurs in the spring, and females lay two to 9 elliptical, hard-shelled eggs in a shallow burrow or under shoreline debris. An unusual behavior is the tendency to share nesting sites; in one case there were 16 nests under a single log. The eggs hatch in late summer or early fall after an incubation period of 100 to 150 days, making this turtle a species that displays delayed emergence. Egg predation is a major cause of mortality, as with many turtle species. In one Pennsylvania population, hatching success was only 15 percent, and predators alone destroyed 25 of 32 nests. Hatchlings are usually less than one inch long and have a very ridged shell which will become less pronounced as they age and will eventually be completely smooth and domed. Its lifespan, as with most turtles, is quite long, with specimens in captivity being recorded at 50+ years of age. The common musk turtle ranges in southern Ontario, southern Quebec, and in the Eastern United States from southern Maine in the north, south through to Florida, and west to central Texas, with a disjunct population located in central Wisconsin. The species now known as Sternotherus odoratus was first described by the French taxonomist Pierre André Latreille in 1801, from a specimen collected near Charleston, South Carolina. At the time, almost all turtles were classified in the genus Testudo, and he gave it the name Testudo odorata. In 1825, John Edward Gray created the genus Sternotherus to include species of musk turtles, and it became Sternotherus odoratus. The species has been redescribed numerous times by many authors, leading to a large amount of confusion in its classification. To confuse it further, the differences between mud turtles and musk turtles are a point of debate, with some researchers considering them the same genus, Kinosternon.