The Snapping turtles are distributed in the Western Hemisphere from southern Canada through the eastern USA, southeastern Mexico, and southward through Central America to Colombia and Ecuador. There are two genera, both highly aquatic, each with one species. Both species have a reputation for biting, and both are of economic importance. Archie Carr described the family and an interesting bit of history this way in his 1952 book, Handbook of Turtles: The turtles of the United States, Canada, and Baja California:
"This small family of large-to-immense, ugly, and aggressive turtles includes only two genera, both of which are American. In 1905 Douglas Ogilby described Devisia mythodes as new genus and species of snapping turtle from the Fly River, New Guinea, and thereby provided an example of discontinuity in range which served zoogeographers as a classic model for years...Dr. Phil Darlington (an entomologist of all things) turned his critical faculty on this situation. He grew suspicious that the locality from which Ogilby's specimen was allegedly collected might not have really been New Guinea at all, since during the subsequent forty years no additional specimens had come to light. His idea encouraged Loveridge and Shreve (1947) to make a careful reappraisal of the charachers of the type, with the result that these writers were able to show conclusively that the famous specimen is nothing but a mislabeled North American snapping turtle, which might well have come originally from Pennsylvania."
The common snapping turtle, Chelydra serpentina (Linnaeus, 1758). Photographed in northern Will County, Illinois, USA. This is a common, widespread species in North America, possibly the most commonly encountered turtle. It is highly aquatic, but it will wander overland in the spring and females leave the water in search of nesting sites in late spring and early summer. Clutch sizes are most likely correlated to the female's body size and clutches of up to 80 eggs have been reported. Eggs require 85-90 days to hatch. It lives in almost all bodies of water and it may prefer those with muddy banks and soft muddy bottoms. It is known to use brackish water habitats in coastal areas. Hibernation aggregations have been reported, and hibernation sites often include muskrat lodges. The snapping turtle is omnivorous, and will take a variety of vegetation, fish, and carrion.
Leeches of the genus Placobdella (Glossiphoniidae) feed on the blood of the common snapping turtle (Chelydra serpentina). These leeches have been found to be vectors for trypanosome infections in snapping turtles, and they drink the turtle's blood from the bone under the scute.
The Alligator Snapping Turtle, Macroclemys temminickii (Harlan, 1835). A sub adult captive above. Below is a juvenile photographed in southern Mississippi, Pearl River drainage. The Alligator Snapping Turtle occurs in the Gulf of Mexico drainage basins from northern Florida to the San Antonia River of Texas. It ranges as far north as central Illinois. This huge turtle rarely leaves the water. Carapace length can reach 660 mm, and it may weigh 80 kg. Alligator Snapping Turtles often use deep water, and it is often in moving water with muddy substrates and aquatic vegetation. Clutches of 8-52 eggs are laid from April to June, and require 100-140 days of incubation. It is omnivorous, but probably more carnivorous that herbivorous. Its worm-like tongue is used as lure to attract fish. Ross Allen and Wilfred Neil reported on this in Archie Carr's Handbook of Turtles (1952).
"Several baby Macrochelys [this name was previously used for the genus], 3 to 4 inches in carapace length, were kept in an aquarium and supplied with life fish. The young turtles would hide between rocks in a corner of the aquarium and open their mouths widely. The muscular base of the lure would then pull don, first on one side and then on the other, imparting a wiggling motion to the two portions of the appendage. Sometimes the turtle would 'fish' for hours without success, but often a Mollienisia or a Gambusia would swim into the open jaws and bite at the 'bait.' The turtles jaws would immediately snap shut on the fish, which was next manipulated into position and then swallowed whole."
