Sea Cucumbers Look Like Aliens When They Eat, and It’s Not Even the Weirdest Thing About Them

There’s plenty of weird stuff going on in the oceans. But here’s something I had never seen before: how a sea cucumber eats. The video is from 2017’s Blue Planet II but recently went viral again on Twitter and came across our feeds. Even if I should have learned it years ago, the way a sea cucumber eats remains very metal. And is definitely more than just a little alien-like. 

Here’s what’s happening in the clip. Like the related sea stars and urchins, sea cucumbers use something called tube feet to walk. They have modified larger versions near their mouth that are sticky. In this case, those tentacles open up to catch things that are floating by. They then bring the food into the sea cucumber’s mouth. It’s the ocean equivalent of a finger-licking good meal. 

There’s a lot of other really weird things about sea cucumbers. According to the Monterey Bay Aquarium, they distract potential predators by expelling their internal organs outside of their body. They can then regrow them later. Seems like a lot more commitment than a lizard regrowing its tail. Scientists are still studying exactly how this works. 

A sea cucumber eats by shoveling food with its sticky tentacle
BBC Earth

Adult sea cucumbers hang out on the ocean floor but babies are free-swimming. As they age, their body shape changes to look like, well, a cucumber. Another fun fact about sea cucumbers is that they breathe through their butts. Sometimes, when they open to pull in water, pearlfish swim inside. This fish then takes shelter inside the sea cucumber and may munch on those internal organs while it’s in there. It must be truly wild to be a sea cucumber.

The Monterey Bay Aquarium Research Institute (MBARI) shares amazing undersea footage, including sea cucumbers, on their YouTube channel. I highly recommend checking it out for other chill ocean vibes and fun facts.

Featured Image: BBC Earth

Melissa is Nerdist’s science & technology staff writer. She also moderates “science of” panels at conventions and co-hosts Star Warsologies, a podcast about science and Star Wars. Follow her on Twitter @melissatruth.