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Sharks Literally Puke Their Guts Out- Here’s Why

Sharks swimming

Sharks are complex and amazing creatures. While lots of research has been done on these graceful predators there is still much scientists want and need to learn. Since sharks can be elusive it is often hard to view them in their natural habitats displaying natural behaviors. This week I stumbled upon this interesting article from


It describes why sharks – when in a stressed state often puke up the entire contents of their stomachs – sometimes including their actual stomach itself. It is a behavior often observed by scientists when they have sharks on their boat for research. Here are some excerpts from this interesting and gross article!


“On November 13th, 2010, marine biologist Austin Gallagher was out on a boat in the Florida Keys, when he and his team pulled an 8-foot-long tiger shark on board to tag it with a satellite tracker. Gallagher was straddling the shark to take measurements, when all of a sudden, “I just saw a huge plume of feathers explode on the back of the boat,” he says.

The shark had just puked a bunch of 8- to 9-inch-long feathers. Gallagher couldn’t believe his luck. He’d heard of sharks vomiting when they’re in high-stress situations, but he’d never seen one before. “Oh my god, this finally happened to me,” Gallagher recalls thinking. “I probably had a huge smile on my face.”

See, when sharks are stressed out, they barf — and not just food. Sometimes they puke out their entire stomachs.

Why? Why do sharks do this? Well, some sharks — like tiger sharks — are voracious eaters that pretty much gobble down whatever they find, including things that aren’t very digestible, like bird feathers, turtles shells, or other bones. If a shark finds itself in a high-stress situation — hooked up to fishing gear, for instance, or stranded on a beach — its instinct reaction is to get rid of that foreign, hard-to-digest food right away.


It might be easier to escape on an empty stomach, says Neil Hammerschlag, a shark researcher at the University of Miami. (Snakes, for instance, are also pukers — they’re known for regurgitating big meals if put under sudden stress after eating.)

Being lifted up on a boat and held down while someone’s taking measurements isn’t exactly your regular, laid-back swim in the ocean — it’s pretty stressful. So it’s not exactly unusual for biologists like Gallagher to encounter shark barf; in fact, he says he’s observed puke from a dozen to two dozen tiger sharks. One in the Bahamas hocked up “amazing stuff,” including huge lobster claws, king crabs, feathers, and the beak of a sea turtle. “That all came out of one tiger shark,” he says.


But why do sharks barf out their entire stomachs? (This has a scientific name, by the way, and it’s called stomach or gastric eversion.) Apparently, it’s just a way for the sharks to cleanse their stomachs. “It’s basically rinsing it out,” Skomal says. A 2005 paper describing such behavior in a Caribbean reef shark seems to confirm that, saying that sharks do this to remove “indigestible food particles, parasites or mucus.”


In fact, rays — which are closely related to sharks — are also known for hurling their stomachs to rinse them out, to remove “noxious material,” according to a 2000 study published in Nature. Don’t worry, both rays and sharks survive the procedure. In the case of the Caribbean reef shark described in the 2005 paper, the animal retracted its stomach back into its body in less than a second and seemed to be doing just fine.


Hammerschlag says he once experienced something even wilder: he was swimming in False Bay, South Africa, when he saw a white shark spew a seal it’d just eaten after being approached by a larger white shark from behind. Maybe the smaller shark was startled? Maybe it didn’t want to get into a fight with the larger shark? In any case, it decided to retch up the seal and then swim away. The larger shark then ate the seal.

“It’s pretty extraordinary, it’s nature in the raw,” Hammerschlag says. “It’s like watching the most amazing documentary, instead you’re kind of living it.””


To read the entire article and see some pretty cool shark videos check out the following link:

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