Red-Ear Turtle

Monday, September 19, 2011

Natural History Notes
by Bob Thomas

The most common water turtle in the Bayou Segnette area is the Red-earred Turtle, Trachemys scripta elegans. These are the little green turtles we used to buy at Walgreens, each with a red stripe behind the eye. As adults, they have shells that are about 10-12 inches long.

The adult females normally retain the green color and the red stripe behind the eye. The males, however, become much darker. Often, the head becomes very dark (may retain a gray stripe behind the eye) and the shell becomes gray with very dark margins along the scales on the back of the shell.

It is obvious that one of the main adaptations in turtles for avoiding predation is having a thick shell. The Red-earred Turtle, one of our most common turtles, relies on a behavioral mechanism that includes aposematic coloration (having a distinct pattern or colors that predators learn to avoid for one reason or another).

Red-eared Turtles (as are the similarly patterned sliders and cooters) are chased and/or eaten by most aquatic predators. Young Largemouth Bass will quickly suck young red-ears into their mouths, hold them for a couple of seconds, then spit them out, never to try another. This is due to the turtle, once in the predator's mouth, clawing, biting and kicking enough to hurt the predator. Since the turtles are distinctly marked, the fish learn not to eat them again.