Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,
Speaker 1: Lauren vocal bamb Here. You probably have a favorite sea
Speaker 1: cucumber and don't even know it. There are over one thousand,
Speaker 1: two hundred species in the world's oceans, so many that
Speaker 1: scientists are even confused about exactly how many there are,
Speaker 1: So there's probably one you'd like a lot. Some of
Speaker 1: them are decked out with the colors of your favorite
Speaker 1: sports team. Others look like somebody crocheted and oversized zucchini
Speaker 1: out of brown aquylic yarn. Even if you weren't particularly
Speaker 1: interested in a living sea cucumber, you might want to
Speaker 1: eat a dead one, or even tape one is medicine.
Speaker 1: But if you don't know already and had to guess,
Speaker 1: would you bet a sea cucumber is an animal or
Speaker 1: a vegetable. They tend to come in tube form, like
Speaker 1: a sweet potato of the sea. They look vegetable ish,
Speaker 1: but they are in fact animals. The thing where we
Speaker 1: refer to them as cucumbers doesn't help. But they're a chinoderms,
Speaker 1: a phylum of marine animals that also includes starfish sea urchins.
Speaker 1: Everybody in this spylum has what's called pentameral symmetry. They
Speaker 1: have five arms arranged around a center point. Of course,
Speaker 1: the kindest thing you can say about a sea cucumber's
Speaker 1: physique is that it looks like a large hogi bun
Speaker 1: that you wouldn't want to eat. But though it more
Speaker 1: closely resembles a slug than a star, the five rows
Speaker 1: of tube feet that extend from its mouth to its
Speaker 1: anus give it the same basic layout as say, a
Speaker 1: very elongated sea urchin that fell over on its side.
Speaker 1: Sea cucumbers have a different approach to reproduction than we do.
Speaker 1: They are usually born either male or female, but can
Speaker 1: change from one to the other during their lives. They
Speaker 1: communicate with each other by releasing hormones into the water,
Speaker 1: which is very similar to their style of reproduction. They
Speaker 1: expel their gam meets those are the egg and sperm
Speaker 1: cells out into the water column and just assume that
Speaker 1: they'll find each other, just as they assume that their
Speaker 1: friend got the hormone message that they left. Sea cucumbers
Speaker 1: eat tiny animals, particles of algae, and general sea junk
Speaker 1: out of the water using frilly tentacles that between meals,
Speaker 1: they keep hidden in their mouths. What they have in
Speaker 1: the way of a brain is a ring of nerve
Speaker 1: cells around their mouth that tells them when it's time
Speaker 1: to eat, burrow into the sand, walk somewhere, or attack.
Speaker 1: And even though they look like tube socks filled with
Speaker 1: modeling clay, a sea cucumbers defense mechanism is pretty terrifying.
Speaker 1: Imagine you're rough housing with a friend or sibling, or
Speaker 1: maybe taking a martial arts class. I'm willing to bet
Speaker 1: that your opponent's defense mechanism would not be to shoot
Speaker 1: out some of his respiratory organs at you out of
Speaker 1: his rear. But that's what ce cucumber combat looks like.
Speaker 1: They have the amazing ability to regenerate the organs that
Speaker 1: they lose this way. Some species but out sticky string
Speaker 1: like spiderwebs to trip up, or and snare their enemies,
Speaker 1: while others have a special toxin that kills or stun
Speaker 1: Small animals don't mess with sea cucumbers, but we do
Speaker 1: mess with c cucumbers all the time. Some species are
Speaker 1: at risk of extinction because in some Asian countries, sea
Speaker 1: cucumbers are the ultimate luxury snack. Some tropical species can
Speaker 1: go for between ten dollars and six hundred dollars per
Speaker 1: kilogram dried in mainland China, and one type retails for
Speaker 1: three thousand dollars per kilo. Sea cucumbers are also used
Speaker 1: in Chinese medicine to treat a variety of ailments like
Speaker 1: muscle aging, compromised immune system, fatigue, and arthritis. Some even
Speaker 1: suggest they could be used in cancer treatments. The varieties
Speaker 1: that are used in food or medicine are becoming increasingly
Speaker 1: rare due to over fishing are over cucumbering. As a result.
Speaker 1: There are around three hundred and seventy seven species of
Speaker 1: sea cucumbers on the Red List of Threatened Species put
Speaker 1: out by the International Union for Conservation of Nature. Seven
Speaker 1: of these are classified as endangered and nine as vulnerable.
Speaker 1: But we need sea cucumbers. Not only are they economically
Speaker 1: important as a seafood, they are essential to ocean ecosystems.
Speaker 1: They're important filtration systems for watery habitats all over the world.
Speaker 1: In some places in the deep ocean, vast herds of
Speaker 1: sea cucumbers roam the ocean floor, gobbling up to tritus
Speaker 1: that drifted down from above. Plus some species provide vital
Speaker 1: services for other marine life. The pearl fish, for instance,
Speaker 1: takes refuge in a c cucumber's anus, and sometimes entire
Speaker 1: schools of pearl fish can find shelter in the rear
Speaker 1: end of a single ce cucumber. They usually don't mind
Speaker 1: much unless they're trying to use their anus to breathe
Speaker 1: at the moment. Oh yeah, c cucumbers breathe through their anuses.
Speaker 1: I forgot to mention that part. Today's episode was written
Speaker 1: by Jesselyn Shields and produced by Tyler Clay. For more
Speaker 1: on this and lots of other bizarre topics, visit our
Speaker 1: home planet, how Stuff Works dot com.