Baby Alligator Snapping Turtle, Florida, 1999

Photograph by George Grall

A baby alligator snapping turtle in a Florida swamp perches on the outsize skull of a record-breaking ancestor. At its largest, the monstrous reptile weighed a whopping 250 pounds (113 kilograms). With its spiked shell, beaklike jaws, and thick, scaled tail, this species is often referred to as the "dinosaur of the turtle world."

(Photo shot on assignment for, but not published in, "Swamp Thing: Unmasking the Snapping Turtle," March 1999, National Geographic magazine)