It is believed that the biggest alligator snapping turtle weighed 400 pounds, according to the National Wildlife Federation, although there is not enough evidence to support the claim. The turtle was said to have been found in the Neosho River and caught in 1937 in Kansas.
National Geographic cites this threatened species as one of the largest freshwater turtles in the world and certainly the largest in North America. A male's shell normally measures roughly 26 inches and its average weight is roughly 175 pounds. Some male alligator snapping turtles have been known to weigh up to 220 pounds.