Sea Cucumber Evisceration

April 9, 2015

If your intestines came shooting out of your butt, you’d probably be pretty upset. But if you were a sea cucumber, that might just be a normal Tuesday.

I’m Anna Rothschild, and this is Gross Science.

Sea cucumbers are marine animals that live in oceans all over the world. They come in a variety of shapes, sizes, and colors, but apart from that they don’t exactly seem like the most charismatic creatures—they spend most of their time inching along the sea floor looking for tasty bits of debris to eat.

But every so often, a sea cucumber will do something totally unexpected--it will eviscerate itself, shooting out its internal organs. This is a process called autotomy, and depending on the species, it can happen in a few different ways. Some species will shoot their intestines, along with some other organs, through their head, while others will shoot them out of their cloaca (which is essentially their butt.)

Now, no one’s quite sure why evisceration happens. It could be to flush out parasites, to withstand times of stress—like when the oxygen levels in the water get too low—or possibly to avoid predation. However, just a side note: some sea cucumbers have a separate set of organs they expel when attacked, called Cuvierian Tubules, and for more on that, check the links below.

Anyway, despite how violent this behavior is, sea cucumbers not only survive evisceration, they’re actually able to regenerate their lost organs. Certain cells in their body “dedifferentiate.” This is a complicated idea, but essentially it means that the cells stop performing their current function, and become capable of doing anything the body requires. These dedifferentiated cells then migrate and start to regrow the lost organs, starting with the gut. And just a few weeks later, the sea cucumber will be good as new.

This regeneration process is totally exciting to scientists. If they could figure out how sea cucumbers dedifferentiate their cells, maybe they could stimulate human cells to do the same thing. If they could, people might one day be able to regrow lost limbs or heal serious spinal injuries. We’re still a long way off, but in the meantime, scientists are studying sea cucumbers, and watching them spill their guts.

Ew.