Pufferfish can do without a functioning stomach

Do you know the puffer fish? You know: that underwater creature that can blow itself up into a ball? Turns out he doesn’t need a working stomach at all.

For us and many other animals, a defective stomach would be a huge problem. We need this stomach to process the food we eat. But the puffer fish solves this differently.

The fish has the body part, but now it is no longer able to produce stomach acid. As a result, the pufferfish’s stomach lost its original function, but was replaced with a new one. When the fish are startled, their stomachs fill with a splash of water, inflating them into a kind of spiky bowling ball, about three times their original size.

But salt water rinses don’t mix well with stomach acids. Researchers have looked into the biology of these and other inflatable fish to find out how they solve this problem. Most can still use their stomach just fine, except maybe right after a moment of inflation. The puffer fish doesn’t, it dissolves it in the rest of its digestive tract and does just fine without gastric function.

Why is the puffer fish the only one to have undergone this change? Perhaps, the researchers speculate, the fish just startled a little more often than other species and simply made it easier to use that stomach just for that.

Read more: Puffer fish don’t need a working stomach, inflate it instead