2012年6月29日 星期五

Getting to Know Your Local Turtles


During a visit to a pond last fall, I noticed a man and several small children leaning over a cardboard box at the edge of the water. As I approached, I noticed a brightly colored brown and yellow turtle crawling out of the box. I watched with a combination of amusement and horror as the man prodded the turtle with a stick towards the pond.

They had rescued the turtle out of the road near their house, and had rushed it over to the pond to return it to its "natural" habitat. But what he apparently did not realize was that the turtle was not an aquatic turtle, but an Eastern box turtle (Terrapene carolina). While these turtles may venture down to the water for a drink or a quick dip, they generally do not swim, and prefer forested or grassland habitats.

I realize that most people are not herpetologists, and may not be able to identify many of the turtles that live with us in our neighborhoods. But even a local stormwater pond can provide an excellent opportunity to become acquainted with some of the more adaptable pond residents. Turtles are an important part of the aquatic ecosystem, and can be easily viewed with a pair of binoculars or a quiet approach.

The painted turtle (Chrysemys picta) is the most widespread turtle in North America. These are the turtles that you see basking in large numbers on partially submerged logs and rocks, although they will quickly slide back into the water at any sign of disturbance. They get their name from the colorful markings on their shells and body. Their upper shell (carapace) is mostly dark, but it has bright reddish-orange crescents around the edges. The head, limbs and tail are brightly striped with red and yellow, and the lower shell (plastron) is yellow-orange. They are omnivourous, and eat insects, plants, algae, fish, and invertebrates.

The red-eared slider (Trachemys scripta elegans) is not actually native to our area. These are the turtles that used to be sold as babies in pet stores until it was found that they could transmit salmonella bacteria to small children. Many of these unwanted pets were released in local ponds, and have been able to survive and breed to form stable populations. They can be easily identified by the bright red marking behind the ear. The carapace is bright yellow and green when the turtles are young, but becomes darker as they mature. Sliders are very similar in diet and behavior to painted turtles. One interesting fact about both species is that they have fixed tongues and no saliva, so they are only able to ingest food in the water.

The common snapping turtle (Chelydra serpentina)is probably the most misunderstood of all pond turtles. Many are intentionally killed each year by humans for fear that they are aggressive, or that they will adversely impact fish populations. While there are reports of snapping turtle bites, this only happens on land when people are harassing the turtles or attempting to handle them. In the water they are actually quite reclusive, and will retreat when approached. Snapping turtles eat a variety of plant and animal materials, and are both scavengers and predators. Although they do eat fish, a few turtles in a pond cannot impact the populations enough to adversely impact the sport fishery.

So grab your binoculars and take a look around the pond to see if you can identify any of these turtles. And if you happen to see a turtle crossing the road, by all means help it out. Put it in the grass on the side of the road where it was heading - it knows where it wants to go!




S. Junior is an aquatic ecologist for Virginia Lake Management, specializing in pond management, GPS lake mapping and aeration for the Mid-Atlantic.





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