Monday, August 25, 2008

Painted Turtles

Painted Turtles
© 2008 Dave Spier.
Perhaps the commonest turtle in New York State is the painted. Often seen sunning itself on a log, and frequently basking in a group, the painted turtle will slide into the water at your approach. It also can be seen crossing roads and a number of people, myself included, are inclined to carefully stop and help the turtle across before it becomes another road pizza.
Painted turtles are recognized by smooth, dark-green or black shells edged with red plus colorful patterns of red and black on their necks and legs and yellow stripes on the head. The local race (subspecies) in the Finger Lakes Region is the Midland Painted Turtle, Chrysemys picta marginata. The average length of the shell is five inches with a record over seven inches. Females are generally larger than males. The large scutes, the pieces that make up the carapace, or top shell, alternate instead of running straight across the back. If you turn the turtle over, the plastron, or bottom shell, often has a dark blotch that individually varies in size and shape. Our subspecies ranges from southern Ontario and New England to Tennessee. Along the east coast, it interbreeds with the eastern race of this species which has a plain, pale plastron.
The painted turtle's diet varies with age. Adults eat mostly aquatic vegetation, but youngsters eat high-protein insects, crayfish, worms, carrion, tadpoles and small mollusks like snails which they find in any shallow body of water, be it pond, marsh, ditch or stream backwater. Lacking teeth, they depend on beaks with sharp cutting edges and inside the jaws are flat, crushing surfaces. Like all reptiles, they are cold-blooded ectotherms that warm themselves from the rays of the sun. The food they eat is used for growth and cell repair and not for generating body heat. As a result they need less food than warm-blooded birds and mammals.
Unlike the amphibians from which they evolved, reptiles have scales or bony plates covering thick, waterproof skin. This reduces loss of body moisture and allows them freedom to roam far from water. In the case of turtles, the bony carapace is fused to the spinal vertebrae and ribs. Once fully grown, the armored shell offers excellent protection against predators. Young turtles are not so fortunate and may be eaten by anything from raccoons to night-herons.
Reptiles differ from amphibians in another important respect. They are not restricted to laying eggs in the water. Amphibian eggs resemble fish eggs and are fertilized externally. Reptile eggs are fertilized internally. Many reptiles, turtles included, lay eggs covered with leathery shells and these are buried on land after digging a hole in damp soil using their clawed hind feet. Painted turtles generally lay half a dozen elliptical eggs in a clutch between mid-May and July. Incubation takes 10 or 11 weeks. Parents never care for their young which are fully developed and totally on their own from birth.
Turtles as an order have been around for an estimated 200 million years. Obviously, their basic design, two external shells connected with a "bridge," has proven highly successful in the survival game. The name "turtle" comes from "tortue," the French word for tortoise. The scientific name, Chrysemys picta, means "golden tortoise painted."
Underwater, basking turtles of the genus Chrysemys have a preference for what fishermen call structure. Fallen branches, logs, weed beds or sharp dropoffs provide escape cover for both turtles and fish. The next time you're out fishing, let the common painted turtle lead you to structure and probably a better catch.
Finally, turtles spend the winter buried in mud at the bottom of communal hibernating ponds. Lying dormant, they obtain oxygen through the linings of the mouth, throat and rear end of the gut. Makes me glad I'm not a turtle.
[For a discussion of the snapping turtle, see the May 21, 2007 issue of the Times of Wayne County: http://www.waynetimes.com/052107.pdf and go to p. 18 of the PDF.]
Send your comments and suggestions to northeastnaturalist@yahoo.com
(This copyrighted article and photograph first appeared in The Times of Wayne County, August 18, 2008. All rights reserved)

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