BrainStuff Classics: What Are Sea Cucumbers?

don't even know it. There are over one two hundred species in the world's oceans, so many that scientists are even confused about exactly how many there are, so there's probably one you'd like a lot. Some of them are decked out with the colors of your favorite sports team. Others look like somebody crocheted and oversized zucchini out of brown acrylic yarn. Even if you weren't particularly interested in a living sea cucumber, you might want to eat a

dead one, or even take one as medicine. But if you don't know, already had to guess, would you bet? A se cucumber is an animal or a vegetable. They tend to come in tube form, like a sweet potato of the sea. They look vegetableish, but they are, in fact animals. The thing where we refer to them as cucumbers doesn't help. But they're a chinoderms, a phylum of marine animals that also includes starfish and sea urchins. Everybody in this hylum has what's called pentameral symmetry. They have

five arms arranged around a center point. Of course, the kindest thing you can say about a se cucumber's physique is that it looks like a large hogi bun that you wouldn't want to eat. But though it more closely resembles a slug than a star, the five rows of tube feet that extend from its mouth to its anus give it the same basic layout as, say, a very elongated sea urchin that fell over on its side. Sea cucumbers have a different approach to reproduction than we do.

They are usually born either male or female, but can change from one to the other during their lives. They communicate with each other by releasing hormone into the water, which is very similar to their style of reproduction. They expel their gam meats those are the egg and sperm cells out into the water column and just assume that they'll find each other, just as they assume that their

friend got the hormone message that they left. Sea cucumbers eat tiny animals, particles of algae, and general sea junk out of the water using frilly tentacles that between meals they keep hidden in their mouths. What they have in the way of a brain is a ring of nerve cells around their mouth that tells them when it's time to eat, burrow into the sand, walk somewhere, or attack.

And even though they look like tube socks filled with modeling clay, a c cucumber's defense mechanism is pretty terrifying. Imagine you're rough housing with a friend or sibling, or maybe taking a martial arts class. I'm willing to bet that your opponent's defense mechanism would not be to shoot out some of his respiratory organs at you out of his rear. But that's what sea cucumber combat looks like. They have the amazing ability to regenerate the organs that

they lose this way. Some species spit out sticky string like spiderwebs to trip uper and snare their enemies, while others have a special toxin that kills or stun small animals don't mess with c cucumbers, but we do mess with C cucumbers all the time. Some species are at risk of extinction because in some Asian countries, C cucumbers

are the ultimate luxury snack. Some tropical species can go for between ten dollars and six hundred dollars per kilogram dried in mainland China, and one type retails for three thousand dollars per kilo. C cucumbers are also used in Chinese medicine to treat a variety of ailments like muscle aging, compromised immune system, fatigue, and arthritis. Some even suggest they could be used in cancer treatments. The varieties that are used in food or medicine are becoming increasingly rare due

to overfishing are over cucumbering. As a result. There are around three hundred and seventy seven species of sea cucumbers on the Red List of Threatened Species put out by the International Union for Conservation of Nature. Seven of these are classified as endangered and nine as vulnerable. But we need sea cucumbers. Not only are they economically important as a seafood, they are essential to ocean ecosystems. They are important filtration systems for watery habitats all over the world.

In some places, in the deep ocean, vast herds of c cucumbers roam the ocean floor, gobbling up to tritus that drifted down from above. Plus some species provide vital services for other marine life. The pearl fish, for instance, takes refuge in a c cucumber's anus. Sometimes entire schools of pearlfish can find shelter in the rear end of a single sea cucumber. They usually don't mind much unless they're trying to use their anus to breathe at the moment.

Oh yeah, sea cucumbers breathe through their anuses. I forgot to mention that part. Today's episode is based on the article c cucumber, animal or vegetable on how stuffworks dot com, written by Jesslynshields. Brain Stuff is production of by Heart Radio in partnership with how stuffworks dot Com and is produced by Tyler Klang. For more podcasts from my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.