Critter Corner No. 11 – Common Snapping Turtle

TurtleBy George Sly I ran across one of these fellows on a recent trip to GPFWA. With water levels at their lowest, I espied a large animal moving across a small island between two shallow pools in the GP 11 basin. Training my binoculars on the movement, a huge common snapping turtle was revealed. Much like the image above, it was well up on its legs and making a determined though ponderous beeline for the next available water. I was struck by the near-prehistoric look of the turtle. In fact, the fossil record shows that its ancestors did indeed share the late Mesozoic world with the dinosaurs. I imagine most people would put the common snapping turtle low on their list of most attractive animals. Nevertheless, this species fascinates me with its ancient visage, stubborn ability to survive, and short-tempered disposition. This irascible nature, particularly when out of the water, seems to be one of the first things we humans learn about the snapping turtle. As boys, my brother and I were once given the task of removing a large snapping turtle from our aunt’s horse pasture. They feared the soft muzzle of one of their fine Arabians was in danger of a good nipping. We coaxed the offending turtle into a large feed bucket and set off intending to deliver it to a nearby pond. My brother had no sooner picked up the bucket than I glanced down and saw the big snapper’s head and neck slowly easing outward from under the carapace. I had the distinct image of a bowstring being slowly drawn to tautness.. “Look out,” I shouted. My brother let go of the bucket handle just as the turtle’s gaping maw shot upward toward his hand. He kept all his fingers but did end up with a surgical-like incision across the knuckles of his middle finger. We did get the turtle to the planned pond but henceforth we both gave all snapping turtles we encountered much more respect. Snapping turtles, of which there are two species in Indiana, belong to a family known as the Chelydridae. This name is derived from a combination of the Greek terms for turtle and water. The geographic range of the huge alligator snapping turtle extends only into extreme southwestern Indiana. This species, which prefers riverine habitats, is the largest freshwater turtle in North America. As a graduate student, I recall seeing one which was in captivity at the Brookfield Zoo in Chicago. At that time, the turtle weighed nearly 220 pounds as I recall. Upon its death in 1982 it had maxed out at 236 pounds. The largest wild specimen known is said to have weighed in at 219 pounds. The alligator snapping turtle is more common in the southern United States but is threatened by overharvesting in some areas. In Indiana and Illinois it is a protected species. The alligator snapping turtle spends much of its time lying under water, in ambush mode, on the muddy substrate. It is unique among turtles in having a fleshy projection of the tongue which is used as a lure to attract prey into range of its jaws. The chelydrids at GPFWA are the eastern or common snapping turtles (Chelydra serpentina). The specific moniker is in reference to the snake-like head and neck of this species. Common snapping turtles, while not nearly the size of their big cousins, are still among the largest of fresh water turtles. The typical range of weights for this species is 20-25 pounds. The late Sherman Minton, Indiana’s preeminent herpetologist, reported seeing a specimen from Noble County (NW of Fort Wayne) that weighed 46 pounds, the largest he had seen. One of the reasons that this turtle is so common is that it is a supreme generalist in regards to the habitats it utilizes. While adults prefer larger, deeper bodies of water common snapping turtles will make use of ponds, ditches, marshes, and the quiet waters of streams. They often wander far from water especially in springtime. Common snapping turtles are also quite catholic in regards to their diet, another reason for their success. Typical food items include aquatic plants, crayfish, frogs, tadpoles, insects, fish, and carrion. Common snapping turtles may hibernate during the winter time. Minton mentions them using muskrat lodges or sheltered areas on the bottom of ponds or lakes. However, these turtles may be active in the winter and have been observed moving about in the water beneath a frozen surface. Common snapping turtles, like other members of the turtle clan, are oviparous which means that they lay eggs. Female snapping turtles dig a nest cavity using their hind feet and deposit eggs into this cavity after which it is covered over. Typically around two dozen eggs are then left (2.5 – 3 months) to hatch on their own. Like some other reptiles the incubation temperature of the eggs determines the sex of the hatchling which will emerge. Eggs exposed to temperatures of 22-28C produce males. Nest temperatures below 20C and above 30C produce females. A study by Wilhoft, Hotaling, and Franks (1983) found that eggs near the surface of the nest usually produced female hatchlings while those on the bottom produced males. The nests of common snapping turtles are vulnerable to predation by raccoons, skunks, and foxes. In Indiana, the common snapping turtle is considered a game species. They may be taken year round. One must have a hunting or fishing license to take any reptile from the wild but as a game species snapping turtles (as well as the two soft-shelled turtles) are subject to bag and possession limits. Go to: http://www.in.gov/dnr/fishwild/3328.htm for more information. By the way, while on the subject of turtles, don’t forget that the eastern box turtle is now a protected species in Indiana. They are not to be taken from the wild. Common snapping turtles are, naturally, of interest to turtle hunters because of their edibility. A quick perusal of the Internet will yield a plethora of recipes for turtle soups and stews. MacGowan, Kingsbury, and Williams in their Turtles of Indiana suggest that the species may be under threat in certain areas because of its use for human consumption. But of course sometimes the turtle wins. Last summer my wife and I sat waiting for a freight train to clear the tracks in southern Sullivan County. At idle In front of us sat a well-used pickup truck, the bed holding an assortment of treasures. As I sat absentmindedly observing the passing train a movement from the truck’s bed caught my eye. At first I thought the passengers had thrown something out the window. But, as I looked more closely, what I saw was a fairly large common snapping turtle lying on its back in the road. Having climbed up the inside of the truck bed and pitched itself onto the road, it was now struggling to overturn itself. With deft exertion of its head and long neck, the turtle quickly flipped itself upright and began to hightail it toward the nearest roadside ditch. I could imagine the disappointment that would result when the truck’s driver found his much anticipated turtle stew no longer existed. For a fleeting moment I contemplated alerting him to the fact that his dinner was rapidly heading for cover. But I didn’t. In soft-hearted acknowledgment of the old reptile’s powerful survival instinct, I gave a silent cheer as it disappeared into the water-filled ditch. I appreciated the fact that one doesn’t survive since the Paleocene without having an attitude and a good dose of toughness. Useful Resources Oktay, Sandra D. 2009. Snapping Turtles. http://yesterdaysisland.com/archives/science/5.php. Yesterday’s Island. Today’s Nantucket. 39 (5). MacGowan, Brian J., Bruce A. Kingsbury, and Rod N. Williams. 2005. Turtles of Indiana. Purdue Extension Publ. FNR-243. West Lafayette, Indiana. Minton Jr., Sherman A. 2001. Amphibians and Reptiles of Indiana. Indiana Academy of Sciences. Indianapolis. Wilhoft, D.C., E. Hotaling and P. Franks. 1983. Effects of temperature on sex determination in embryos of the snapping turtle, Chelydra serpentina. J. Herp. 17: 38-42.