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  • {♫Intro♫}

  • There are plenty of creatures out there

  • with only one opening to handle the business of both taking in food and getting rid of

  • the leftovers.

  • Jellyfish, for example, get along fine with a mouth that's also an anus.

  • But there's at least one animal out there that doesn't have a gut openingat all.

  • The giant tube worm Riftia pachyptila lives over a kilometer deep in the ocean, along

  • ocean ridges, where hydrothermal vents are common and spew boiling hot, chemical-laden

  • water into the freezing cold deep sea.

  • These chemicals include stuff like hydrogen sulfide, which isn't all that great for

  • most animals.

  • But these bizarre-looking worms are adapted to live in this hostile habitat, without so

  • much as a mouth to make things easier.

  • Riftia almost look like a lipstick, with their vivid red plumes and tube-like outer casing.

  • Within, they have a structure called a trophosome, which is like a gut, but with no way in or

  • out.

  • They were first discovered in 1977 when the submarine ALVIN accidentally landed on a cluster

  • of them while it was investigating hydrothermal vents near the Galapagos.

  • Red blood gushed up around the sub.

  • The researchers on board later discovered that the tube worm's plume has blood vessels

  • full of hemoglobin.

  • In us mammals, hemoglobin is mainly responsible for transporting oxygen.

  • In Riftia, the tube worm's plume acts like a gill.

  • Its hemoglobin helps pull that hydrogen sulfide from the vent water and move it into the trophosome.

  • Inside the trophosome are millions of symbiotic bacteria, accounting for up to half the body

  • weight of the worm.

  • The bacteria are able to convert the toxic vent water chemicals into a food source for

  • the worm, through a process called chemosynthesis.

  • Much like plants use photosynthesis to produce food using sunlight, these bacteria are getting

  • their food through chemical reactions that use hydrogen sulfide to produce energy.

  • And the inside of a worm is a much better habitat for them than the open vents -- or

  • so the hypothesis goes.

  • Not only have the bacteria turned this hostile environment into an advantage -- the worms

  • have capitalized right along with them.

  • They don't need a mouth or anus -- they just get fed by their bacterial partners,

  • which produce enough food to keep everyone happy.

  • It's like having your kitchen inside your body!

  • OK! So that's how the food gets in, but how does it get out?

  • well the waste produced from digesting this food can be transported back out via the worms'

  • bloodstream, there's no need for either a mouth or an anus.

  • But it begs the question: How do those personal chefs get there?

  • Researchers asked this question in 2006 and found that it's… weird!

  • The bacteria enter through the tube worm's skin when it's still a larva.

  • It's basically a bacterial infection.

  • Hydrothermal vents are an unpredictable place to call home, thanks to the constant tectonic

  • activity happening along ocean ridges.

  • They may be there one day and gone the next.

  • Once the vents stop venting, the tube worms die because their bacteria's food source

  • gets cut off.

  • The distance between them can be several miles, which is a long swim when you're a little worm.

  • So researchers aren't sure how tubeworm larvae get from place to place without a food source.

  • Hypotheses range from whale falls to shipwrecks

  • -- which would supply enough of the chemicals

  • the bacteria need to stay alive.

  • The discovery of these weird worms and their unique way of eating has led to researchers

  • finding chemosynthetic communities in ecosystems around the world -- from elsewhere in the

  • ocean to Yellowstone National Park.

  • Who knew a giant, mouthless, buttless worm could completely redefine the way we thought

  • about how life works on our planet?

  • Thanks for watching, and thanks to our patrons for helping us bring this video to the world!

  • What world would it be without it!

  • If you want to help out and join our amazing community of supporters, check out patreon.com/scishow.

  • {♫Outro♫}

{♫Intro♫}

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