Basking Turtles
Visit Knoch Knolls on a warm afternoon in the summer and you're likely to see turtles basking in the sun on a log in the pond outside. Turtles and other reptiles depend on exposure to the sun to keep their bodies warm. Reptiles are ectotherms, meaning they do not metabolize food to keep their bodies warm, but rely on their environment for warmth. In winter or other times when the environment is not ideal, reptiles will go into a period of brumation, or low activity, almost like hibernation. If you visit the pond in the winter, the turtles will probably be brumating under the icy surface.
Like other reptiles, turtles have scales on their skin, lungs for breathing air, and a three-chambered heart. June is egg laying month for turtles, the time when you are most likely to see female turtles leaving the water in search of a spot to lay their tough, leathery eggs. When the eggs hatch, the young are considered precocial, which means they are able to survive on their own without any parental care. What makes turtles special anatomically is that their backbone and ribs are fused to the inside of the top half of their shells. The top of the shell is called the carapace, and the half of the shell under the body is called the plastron. Turtles are notorious for being long-lived. In North America, many of the turtle species boast lifespans equivalent to those of humans: from 50 to 80 years!
In the pond at Knoch Knolls Park you may see two types of turtles. The first type is the common snapping turtle, Chelydra serpentina, shown below to the left. Common snapping turtles, grow to about 18 inches, but farther south in Illinois you might also encounter alligator snapping turtles. Snapping turtles are predatory, but they don't work very hard for their food. Snapping turtles hunt for their prey through ambush, so it's not uncommon to see a snapping turtle sitting in the same spot day after day, waiting for its next meal. They have large, sharp, bony beaks for catching their prey, so watch out! If you see a snapping turtle basking on your driveway or crossing the road during egg-laying season, don't try to pick it up with your hands; instead, use a shovel. They are able to stretch their neck and head around the side of their bodies and bite. Because of their fierce tempers, sharp beaks, and large size, snapping turtles don't use their shells for protection the way other turtles do. A snapping turtle cannot hide in its shell because the plastron is too small to cover the animal's body completely. You are more likely to see snapping turtles in the spring when the females are out looking for nesting sites.
The second types of turtle you might see basking in our pond are often referred to as pond turtles. The most common "pond turtles" at the Knoch Knolls Park are painted turtles, Chrysemys picta, and red-eared sliders, Trachemys scripta elegans. Painted turtles, shown above right, are native to most of North America, and they're easy to spot because of the distinctive red, orange, and yellow markings on their heads and carapaces. Painted turtles spend almost their entire lives in the water. While primarily vegetation feeders, painted turtles also will eat tadpoles and small minnows, as well as detritus material in the pond. Red-eared sliders, shown above middle, are larger pond turtles which are native to the southern part of the U.S. but not Illinois. If you see one at Knoch Knolls Park it may have been someone's pet for a while before being released (illegally) into the surrounding area. You'll know you've spotted a red-eared slider when you see the characteristic red stripes behind the animal's eyes.
