The spotted turtle ( Clemmys guttata), the only species of the genus Clemmys, is a small, semi-aquatic turtle that reaches a carapace length of upon adulthood. Their broad, smooth, low dark-colored upper shell, or carapace, ranges in its exact colour from black to a bluish black with a number of tiny yellow round spots. The spotting patterning extends from the head, to the neck and out onto the limbs. Sexually mature males have a concave plastron and a long, thick tail. By contrast, sexually mature females possess a flat plastron and have a tail that is noticeably shorter and thinner than that of mature males. Mature males also have a dark iris and face; females typically have a yellow or orange iris and a similarly coloured face that is distinctly lighter than the males'. Juveniles appear female-like in this regard, and at maturity males begin to develop darker features.
Spotted turtles are aquatic omnivores that inhabit a variety of semi-aquatic or in other words, shallow, fresh-water areas such as flooded forests, marshes, wet meadows, bogs and woodland streams in southern Canada (Ontario) and the eastern United States: the eastern Great Lakes and east of the Appalachian Mountains.
Visual differences between male and female turtles develop around the time of sexual maturity. The male spotted turtle has a tan chin, brown eyes, and a long, thick tail. The chin of the female is yellow; she also has orange eyes and a shorter tail than the male. In addition, the bottom shell of males is concave while it is either flat or convex in females. On average, females grow to be slightly larger than males. Also, females have more spots than males (on average).
Hatchlings resemble the adults closely. Consistently, each segment of the upper shell has only one yellow spot.
The spotted turtle occupies a variety of habitats including swamps, bogs, fens, marshes, woodland streams, and wet pastures. Also, brackish streams that are influenced by tides can also serve as a home to this turtle in addition to ditches, vernal pools, and sedge meadows. For a habitat to be sufficient for spotted turtle survival it must have areas of soft substrate and at least some aquatic vegetation. An optimum habitat would include shallow and slow-moving waters with soft muddy soil, sedge tussocks, water lilies, sphagnum moss, and cattails. Because it is so often found in areas that contain Lemnoideae, the yellow spots on these turtles may serve as a form of camouflage. The spotted turtle avoids artificial reservoirs and deep, open-water areas.
The spotted turtle can be decidedly terrestrial, spending a good amount of time on land and sometimes Ectotherm on patches of grass near its body of water. The females during times of nesting will travel onto land and lay eggs on sunny soil. Nesting also may take place in other terrestrial locations, for instance near man-made dikes or the nest of a muskrat.
Despite the seemingly large number of populations in Canada, many are not self-sustaining because of the following reasons: the majority of the populations are small, they all have less than 200 individuals, and the areas are all isolated from one another. All told it is estimated that anywhere from 1000 to 2000 spotted turtles live in Canada however, with individual populations ceasing to exist, this number is declining.
The spotted turtle's range overlaps that of many other turtles. It can often be found in the same wetlands as , , snapping turtles, , Blanding's turtles, eastern box turtles, common musk turtles, and eastern mud turtles.
During the freezing temperatures of winter and the extreme heat of summer, spotted turtles become inactive during environmentally unfavorable conditions. However, the species appears to be relatively tolerant of drought conditions. Spotted turtles do become active very early in the spring, and are often active at relatively cold water temperatures during that season. Activity appears to peak during April and May in the northern part of the range. In the warmest part of the summer (when water temperatures exceed 30 °C), they may aestivate terrestrially or aquatically for long periods of time. During summer dormancy, the turtles may burrow into leaf litter in woodlands or marsh edges or open fields; others remain in muskrat burrows or other aquatic refuges. Litzgus and Brooks (2000) have questioned the common presumption that summer dormancy is an attempt by the turtles to avoid high temperatures; data from Ontario and elsewhere suggests that avoidance of predation and conservation of energy resources may be viable alternate explanations. No matter the explanation for dormancy, the "winter" dormant period may commence in late summer or fall, but in almost every instance after a return to aquatic habitats.
Spotted turtles home ranges tend to occupy limited areas of about 0.5 to 3.5 hectares (1.2 to 8.6 acres). Note that due to their size, these small turtles are highly vulnerable to predation, particularly during their frequent terrestrial wanderings. Many specimens will show mutilation injuries and scars from past predation attempts. Raccoons ( Procyon lotor) are particularly adept at consuming and killing this species. Spotted turtles have been observed to dive into the water and bury themselves in the bottom mud when surprised while basking. Muskrats kill many spotted turtles during the winter dormant period.
Habitat destruction, alteration, and conversion, collection for the pet trade, and other human impacts such as vehicle mortality (cars and mowers) are leading to declines in populations. Vehicular mortality is particularly impactful because turtles crossing roads are likely pregnant female turtles in search of a nesting site. Additionally, since reproductive rates of these turtles are low, spotted turtles are extremely susceptible to population impacts.
Due to their aquatic habitat, these turtles are particularly sensitive to pollutants and toxic substances. They will disappear rapidly from areas with declining water quality.
Distribution
Reproduction
Population features
Ecology and behavior
Diet
Notes
Conservation
Actions to benefit the species
Bibliography
Further reading
External links
|
|