Snapping turtles in our lakes

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Last summer, I encountered this big fella crossing the bike path along Lake Mendota, near where Willow Creek comes into University Bay.  No doubt these turtles inhabit all our lakes and small ponds.

Common snapping turtle near Lake Mendota.

Last summer, I had a chance to learn more about snappers.  While walking on the shore of a pond in Cape Cod, I spotted some mysterious tracks (below)--three inches across, with enormous claw marks and a heavy tail drag mark.

It wasn't long before I began to suspect the River Otter. Large males can have tracks that big, and river otters do live in most unpolluted waterways in the US.

I sent my photos to two wildlife experts: Scott Craven and David Brown. Craven suspected either snapper or otter--but he thought the tail drag was too heavy for an otter, which seldom leaves tail marks. Brown was positive it was a common snapping turtle Chelydra serpentina, and said the holes in the sand were also caused by the turtle. Mystery solved!

The foot prints are roundish, with deep claw marks around the edge. You don't see marks from the shell, because snappers walk with the shell off the ground.

Excavations, probably by the snapper, as she looked for a place to lay. Photo of female laying.

These holes were likely made by a female snapper digging with her front feet as she looks for a place to dig her nest. If the nest had been finished and covered, you wouldn't be able to find it. If it had been plundered by a raccoon, you would see eggshells scattered about.

It's likely the snapper found this wet spot unsuitable for a nest, since the water was only a few inches down. Pond turtles require dry, sandy places for their nests, and there weren't many places available at this pond--with so many woods around. Another attempted hole nearby suggested this was one frustrated turtle, looking urgently for a place to lay her eggs!

Females may travel long distances over land, looking for a place to lay. This makes them vulnerable to being run over.

Common snapping turtle, from Wikipedia commons.



Snappers can grow up to 80 pounds and live for 30 years in the wild or 50 in captivity. They look like ancient reptiles--and indeed they are. They are little changed in form from well before the time of the dinosaurs.

But snappers have survived into the modern world because being cold blooded has its advantages. With a very slow metabolism, snappers can hold their breath for a half hour or more. They are often ambush predators, waiting motionless below the surface for a fish or frog to happen by. Then, the long neck strikes with lightning speed, and the surprised prey is eaten with a few gulps.

Snappers may bury themselves under the mud in shallow water, waiting for something edible to happen by. When they need to breathe, they simply raise their long neck to the surface.

Young snappers eat insects, worms, leeches, crayfish, small fish, or dead animals. Adult turtles eat larger prey including frogs, toads, snakes, turtles, small mammals, and even ducklings. Both eat plants as well, for a third of their diet.

Being rather fierce--and protected by scales and strong jaws--snappers don't require as much protection from their shell. They look like they have badly outgrown their shells--seeming to bulge out of them.

Snappers won't attack swimmers, but if you pick them up, they have very long necks that can take a serious bite--even remove your finger.

Don't confuse the common snapper with the alligator snapping turtle Macrochelys temminckii, found in southern states. The record for an alligator snapper was over 260 pounds. These turtles look much more fierce and primitive than the common snapper. Their most distinctive feature is a worm-like red lure on the bottom of their mouth. They open their jaws wide to display the lure, and wait....

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Find out more about snappers

Popular snapping turtle website
Wikipedia articles on common snappers and alligator snappers.