Common musk turtle

Appearance

Stinkpots are small black, grey or brown turtles with highly domed shells. They grow to approximately 5.1–14 cm and average in weight at 603 g . They have long necks 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. Their plastrons are relatively small, offering little protection for the legs, and have 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.

Distribution

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.

Status

Though the common musk turtle holds no federal conservation status in the US and is quite common throughout most of its range, it has declined notably in some ares, and appears to be more sensitive than some native species to human degradation of wetlands. It is listed as a threatened species in the state of Iowa. It is listed as a species at risk in Canada, and is protected by the federal Species at Risk Act . It is also protected under Ontario's endangered species act. In this part of its range, only wetlands with minimal human impact have robust populations. Road mortality of breeding females may be one of the problems associated with human development.

Behavior

Musk turtles are almost entirely aquatic, spending the vast majority of their time in shallow, heavily vegetated waters of slow moving creeks, or in ponds. They typically only venture onto land when the female lays her eggs, or in some cases, to bask. They can climb sloping, partially submerged tree trunks or branches to as much as 2 m above the water surface, and have been known to drop into boats or canoes passing underneath.Their defense mechanism is to excrete a musk scent from a small gland in their underside, hence the name musk turtle. This is used to scare away predators and natural enemies.

Habitat

This turtle is found in a variety of wetland habitats and littoral zones, particularly shallow watercourses with a slow current and muddy bottom. Although they are more aquatic than some turtles, they are 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, they must nest on land, and shoreline real estate development is detrimental. They hibernate buried in the mud under logs, or in muskrat lodges.

Reproduction

Breeding 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. 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. Their lifespan, as with most turtles, is quite long, with specimens in captivity being recorded at 50+ years of age.

Food

They are carnivorous, consuming a wide variety of aquatic invertebrates including crayfish, freshwater clams, snails, aquatic larvae, tadpoles and various insects. They 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. Wild turtles often will not hesitate to bite if harassed. A musk turtle's neck can extend as far as its hind feet; caution is required when handling one.