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As far as research goes, it sounds pretty intense: pumping the stomachs of 500-plus alligators — "live and alert" ones at that. It was part of James Nifong's study on whether American alligators on the Atlantic and Gulf coasts eat sharks, and the answer might surprise you: yes.

A small variety of sharks, that is, but a press release calls it the "first scientific documentation of a widespread interaction between the two predators." In fact, the Kansas State University researcher tells National Geographic that when he first broached with alligator experts the question of whether alligators eat sharks, some of them thought he was kidding.

Nifong wasn't, and he found that in addition to the expected prey —crustaceans, fish and wading birds, per his study in Southeastern Naturalist — he documented alligators eating a lemon shark, a nurse shark and a bonnethead shark, along with an Atlantic stingray.

This, even though sharks and rays are not freshwater creatures.

Nifong explains it's not uncommon for sharks to enter freshwater, where "opportunistic alligators" then pounce. GPS trackers also found the gators wade into estuaries where the two types of water mix, and where shark nurseries can be found.

But it may be a two-way street. Says Nifong, it's "really about size dynamic. If a small shark swims by an alligator and the alligator feels like it can take the shark down, it will, but we also reviewed some old stories about larger sharks eating smaller alligators." (An alligator was involved in this strange animal skirmish.)

This article originally appeared on Newser: Battle of the Jaws: Study Finds Alligators Eat Sharks