On Aug. 4, Port Charlotte resident Tammy Shaw was paddleboarding in Silver Springs State Park in Florida, when she discovered a gruesome scene of cannibalism and carnage. A sizable alligator crouched in the spring just a short distance from Shaw's inflatable boat, and clasped in its jaws was the limp body of another alligator — the bigger predator's next meal, News 6 Orlando reported.
As Shaw watched, the large gator lifted its head higher and then slammed its unresponsive prey into the water.
Shaw captured a short video of the gators and posted it in the Facebook group Alligators of Florida on Aug. 10. Commenters were shocked that an alligator would eat another alligator. "I never knew they would actually eat one of their own," one person wrote.
Yet cannibalism is not at all uncommon in alligators, Adam Rosenblatt, an assistant professor of biology at the University of North Florida who studies American alligators (Alligator mississippiensis), told Live Science in an email. Alligators eat other alligators for the same reason they eat anything else, he explained — they get hungry.
"Alligators will eat anything they can fit their jaws around, including mammals, birds, reptiles, amphibians, fish, insects, crustaceans, snails, and even fruits and seeds sometimes," he said.
It's also possible for alligators to eat other alligators that invade their territory, Rosenblatt added. Large male alligators, in particular, are often solitary and territorial, according to the conservation nonprofit Defenders of Wildlife.
Alligators are master hunters, and not only when it comes to eating other alligators. They often simply swim directly up to small prey, like crabs and shrimp, and immediately gulp them down, Rosenblatt said, but with larger prey, such as pigs and deer, alligators can be very stealthy. Gators sometimes wait in the water for hours for big animals to approach to get a drink, before slowly advancing to avoid notice and then suddenly striking when they are 3 or 4 feet (about a meter) away.
"They'll grab the prey by the head or by a leg, whatever the gator can get its mouth on, then drag the prey into the water to drown it," Rosenblatt said. Alligators also sometimes do a "death roll," where they quickly roll while holding prey, often breaking the prey's neck or legs. Gators also kill turtles by using their powerful jaws to crush the turtles' shells, he said. Alligators devour small prey whole, but with large prey, they vigorously shake it — as demonstrated by the bigger alligator in Shaw's video — so that it will more easily break up into smaller pieces, according to the Smithsonian's National Zoo and Conservation Biology Institute. If the prey is very large, alligators use their death roll to tear it apart.
Though cannibalism is taboo in most modern human cultures, it's very common among many animals, Rosenblatt said. For example, lions and chimpanzees are also known to eat their own kind. But even if people are squeamish about such observations, alligators won't be changing their cannibal dining habits anytime soon.
"Alligator cannibalism has occurred for millions of years and will continue to occur," Rosenblatt said. "There's no reason to expect its frequency to change in the near future."
Originally published on Live Science.
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Rebecca Sohn is a freelance science writer. She writes about a variety of science, health and environmental topics, and is particularly interested in how science impacts people's lives. She has been an intern at CalMatters and STAT, as well as a science fellow at Mashable. Rebecca, a native of the Boston area, studied English literature and minored in music at Skidmore College in Upstate New York and later studied science journalism at New York University.