The Carlisle Mosquito Online

Friday, April 30, 2004

Features


Eastern Painted Turtle

Today, the last Friday in April, is National Arbor Day. It's also the last day of National Poetry Month and I reflect, "Never can our human will, be calm and tree-like, free and still." Of all the spring things happening, I chose the painted turtle which has a particular fondness for trees, or at least fallen tree trunks, logs and branches on which to bask in the sun — in a manner rather calm and tree-like, free and still.

Name: Chrysemys picta or Painted Turtle. There are four subspecies — this one is the Eastern Painted Turtle, Chrysemys picta picta.

When and where seen: I saw about a dozen on April 10 in the pond at the Maple Street bridge. They were there again on Patriots Day, and on April 25. You will probably be able to see them, with binoculars, on any warm day at any of the permanent ponds in town. They are quite common.

Talking turtle: "Turtle" is the all-encompassing term for reptiles with shells. Tortoises and terrapins are subsets of turtles. Tortoises are turtles with land-dwelling adaptations like thick legs and no webbing between the toes; terrapins are less well defined — they seem to be small turtles destined for human culinary purposes. The upper turtle shell is called a carapace; the underside shell is a plastron; both the top and bottom shells are covered with plates called scutes.

Characteristics: The Eastern Painted Turtle has a smooth black or dark olive carapace. The scutes are lined up in rows, which distinguishes this turtle from the other three subspecies of painted turtles. There are light lines running across the carapace where the front edges of the larger scutes are aligned. The most striking characteristic is the red and yellow paint job on the legs, neck, face and head. Yellow stripes under the chin and red stripes along the neck and legs stand out boldly against the dark background. The edges of the carapace are marked with bright red and orange. The Vernal Pond Field Guide says that the plastron is plain yellow or cream-colored with no markings. I have seen a painted turtle with very distinct yellow lines running from side to side across a pale orange plastron.

Life Cycle: In June, you may see a solitary female painted turtle away from the water, looking for an open area for nesting. I found the one in the photograph in my back yard last year on June 18. The female digs out a nest with her hind feet, often digging several false nests before laying her clutch of four to eight eggs. If the eggs are not eaten by skunks, foxes, raccoons or other predators, they will hatch in late summer. The young hatchlings are vulnerable to predators like frogs, snakes, wading birds and fish. The survivors reach breeding age in four to six years. Painted turtles spend the colder parts of winter in soft mud on the bottom of the pond and in late winter they can sometimes be seen swimming around if the ice is clear. Spring is time for courting, mating, and starting their very common behavior of basking.

Basking: Basking is a way of life for painted turtles. If there are insufficient basking sites, the turtles will stack themselves on top of one another up to four to five turtles deep. Basking has several purposes. It raises the body temperature to a level that improves digestion of food; it makes them more agile in escaping predators; the sun and the dryness of the air can cause parasites to dry up and drop off; the dry air slows the growth of algae on the shell; and it seems as if ultraviolet light is needed to synthesize vitamin D for a strong healthy shell. Painted turtles are very alert while basking. They quickly disappear into the water at the slightest sign of disturbance.

References: Thomas F. Tyning, Stokes Nature Guides, Guide to Amphibians and Reptiles; Leo P. Kenney & Matthew R Burne, A Field Guide to the Animals of Vernal Pools; tree poem quote is from R.G.E by Richard Eberhart.

Anyone can write the Biodiversity corner about any living thing, animal or vegetable, that exists in the wild and was seen in Carlisle. Or tell me what you've seen, or send me a photo, and I will write the column. Send the information to kayfair@aol.com or to Kay Fairweather, 392 School St.


2004 The Carlisle Mosquito