Featured Image Credit: Walter Heim/NOAA
By Kira Krall
Ever been so nervous, you feel like you’re going to cough up your own stomach? Sharks actually do!
Many different species of shark have been documented regurgitating the indigestible parts of whatever they recently ate. Sometimes the stress response is so severe that they vomit up their stomachs. This gastric eversion is triggered by a stress response, but the behavior itself may be a natural occurrence.
Purging their stomach contents gets rid of anything the shark’s stomach acid can’t break down. Sharks have been seen spitting up natural leftovers like feathers, sea turtle beaks, and lobster claws. Parasites and mucous are also unwelcome guests in the bellies of the beasts.
Gastric eversion works a little differently than humans tossing their cookies. While the contractions of the esophagus and relaxation of the stomach are similar, it seems to be completely voluntary. The sharks willingly manipulate their digestive organs, then suck their stomach back in once the offending contents are ejected. The whole process often takes less than a second. Watch the video below!
Tiger sharks are the most well-known purgers largely due to what they eat: everything. One study of the South African population showed that the only thing that matters to a tiger shark is how large the prey is. Unfortunately non-prey items often end up in the line of fire. A chicken coop, a raincoat, and a can of peas are just some examples of the crazy things people have found in a tiger shark stomach.
Great white sharks also exhibit gastric eversion, but theirs is a unique variety. After consuming large quantities of whale carcass, they regurgitate some of the meat and go back for more. There are theories that suggest that the great whites may be cleansing their system of poor-quality meat and are making room for a better bite.