Snapping turtles survived mass extinction that killed dinosaurs
By Matthew R. March, MNRD
Polk County Extension Agent
Creeks, rivers, lakes and ponds of Polk County are home to turtles that many people think look more like a dragon then a modern-day turtle. A first look at these turtles conjures up images of a long-ago period when dinosaurs ruled the earth. The turtles I am referring to are snapping turtles and, in fact, their ancestors did roam the earth some 70 million years ago during the cretaceous period along with such dinosaurs as t-rex and velociraptor. Polk County is home to both the common snapping turtle (Chelydra serpentina) and the alligator snapping turtle (Macroclemys temminckii), both of which belong to the turtle family Chelydridae. The alligator snapping turtle is the only extant species in the Macroclemys genus, while the common snapping turtle is one of three extant species in the Chelydra genus.
Both the common and alligator snapping turtles are at the top of the food chain in the aquatic worlds they live in. They have large heads with large jaws leading to their nickname loggerhead. They rarely bask in the sun like other turtles and will barely extend their nostril above the water for air. Most of the time these turtles remain on the bottom of lakes, ponds, rivers, creeks and swamps. For this reason, they are rarely seen. Common snapping turtle is more of an active predator and will search for its food which includes aquatic invertebrates, fish, reptiles, birds and even a large amount of carrion and vegetation. Alligator snapping turtle is an ambush predator and will bury its body in mud and will hold its mouth open. Inside its mouth is a pink appendage that resembles a worm when wiggled lures fish to the open jaws. Both turtle species have incredibly strong jaws that close quickly. These jaws can easily cause serious injury to fingers and toes. While snapping turtles tend to be aggressive on land, they tend to be docile in the water and usually do not bite when stepped on. Snapping turtles cannot enclose themselves in their shells for protection like other turtles. Their plastron (bottom shell) is very small. Snapping turtles’ defensive method is to be aggressive when threatened since their fleshy legs, neck and head are always exposed.
Common snapping turtle average weight is 10-35 pounds but can reach up to 75 pounds. The tail has several bony protrusions making their tails saw-toothed in shape. The carapace (top shell) is rough in nature when young but becomes smoother in adults. Young individual shells will be edged with light spots and have one row of scutes on side of the shell. Common snapping turtles can be found wherever water is found, from bar ditches to large lakes. Their range extends roughly across all the U.S. east of the Rocky Mountains. Populations can also be found in southern Canada and northern Mexico.
Alligator snapping turtles weigh in at 35-150 pounds with a record of 251 pounds. The tail is very long especially on young individuals but will not have the saw-toothed tail like in common snapping turtles. Alligator snapping turtles can easily be recognized by their large heads with strongly hooked beaks. The carapace is very rough with three prominent ridges. There is an extra row of scutes on the side of shell. Alligator snapping turtles tend to be found in larger creeks, rivers and lakes. The turtle is found in the southeast and northward to Iowa along the Mississippi watershed. In Texas, they are found roughly along and east of the Trinity River.
Snapping turtles are considered a popular delicacy in some locations and because of this, over-harvesting has caused population declines for alligator snapping turtles. In Texas, the alligator snapping turtle is considered a threatened state species and is protected from harvesting, killing or harassment. It has also been considered a species that may need to be federally protected. To ensure the continuation of this ancient dragon that has been around for 70 million years, you should immediately return any alligator snapping turtles you catch to the water.