WEBVTT - How Does the Slow Cone Snail Catch Prey?

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<v Speaker 1>Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff. Lorn

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<v Speaker 1>Bogelbaum here. Cone snails are a group of around a

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<v Speaker 1>thousand species of venomous, predatory marine snails that live in

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<v Speaker 1>shallow tropical waters around the globe. Their pretty, cone shaped

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<v Speaker 1>shells are intricately patterned and brightly colored, apprized by seashell collectors,

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<v Speaker 1>and their venom is fascinating to biomedical researchers and science

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<v Speaker 1>fiction writers alike, a pretty high profile for a very slow,

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<v Speaker 1>not particularly aggressive animal that spends its days toddling after worms, fish,

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<v Speaker 1>and other snails for dinner. For example, In the real world,

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<v Speaker 1>their venom has been used in therapies from diabetes treatment

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<v Speaker 1>to terminal pain management. And this is a little bit

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<v Speaker 1>of a deep cut, but take the Jurassic Park film

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<v Speaker 1>sequel of the Lost World. In the movie, an air

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<v Speaker 1>gun with venom darts is used to take down Peschi dinos.

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<v Speaker 1>The active ingredient is purported to be an enhanced venom

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<v Speaker 1>from the cone snail species Conus propuis, ends, of which

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<v Speaker 1>the movie says is the most powerful neurotoxin in the world.

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<v Speaker 1>Before the article, this episode is based on how stuff

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<v Speaker 1>work spoke with Helena Safavi, an assistant professor of biochemistry

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<v Speaker 1>at the University of Utah who studies conesnails and their venom.

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<v Speaker 1>She said, in the movie, the venom is described as

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<v Speaker 1>the most powerful neurotoxin in the world that acts within

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<v Speaker 1>one two thousandth of a second, faster than the velocity

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<v Speaker 1>of nerve conduction. None of this is true, but nevertheless

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<v Speaker 1>very entertaining. Conesnails are very slow animals that cannot graze

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<v Speaker 1>on algae like their non venomous snail relatives, but also

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<v Speaker 1>have no means of mechanical prey capture. That is to say,

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<v Speaker 1>they can't bite or grasp like a shark or cat.

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<v Speaker 1>And despite the lack of teeth and claws, all cone

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<v Speaker 1>snails are impressive predators. Safavi said a when a slow

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<v Speaker 1>animal wants to hunt other creatures, it has to evolve

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<v Speaker 1>potent venom to be successful. Particularly those cone snails that

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<v Speaker 1>prey on fish have to have toxins that can potently

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<v Speaker 1>immobilize the fish prey before it swims away. One of

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<v Speaker 1>the most remarkable things about the thousand ish species of

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<v Speaker 1>cone snail is that there's almost no overlap in the

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<v Speaker 1>toxins that are made by each A Safavi said, this

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<v Speaker 1>shows how fast these toxins evolve. Even very closely related

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<v Speaker 1>species have only around five to ten percent overlap, with

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<v Speaker 1>each species making several hundreds of toxins. One can estimate

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<v Speaker 1>that there are around half a million different toxins present

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<v Speaker 1>in cone snails. Because their venoms are unique to specific species,

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<v Speaker 1>some species deliver a very minor sting and others could

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<v Speaker 1>kill you. A Safavi explained there are about forty known

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<v Speaker 1>fatalities by con snails, and nearly all, if not all,

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<v Speaker 1>were caused by a single species. Conus geographis commonly known

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<v Speaker 1>as the geography cone. Some of the toxins in this

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<v Speaker 1>species can cause acute respiratory failure and potentially heart failure.

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<v Speaker 1>It's also one of the species that can inject larger

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<v Speaker 1>quantities of venom compared to most other cone snails. Compared

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<v Speaker 1>to snakes and even scorpions and spiders, death from cone

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<v Speaker 1>snail stings are extremely rare. Cone snails might not have fangs,

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<v Speaker 1>but most have a venom covered harpoon that they use

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<v Speaker 1>to incapacitate their prey. Okay mollusks, like snails, often have

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<v Speaker 1>a radula a type of combination tooth and tongue structure.

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<v Speaker 1>It's often a ribbon like structure with many tiny teeth,

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<v Speaker 1>and it helps them scrape up or cut down food.

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<v Speaker 1>In the case of cone snails, the radula has a

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<v Speaker 1>venom sack at its base and it's barbed at the

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<v Speaker 1>other end it can dart out. It's some four hundred

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<v Speaker 1>miles an hour. That's about six hundred and fifty kilometers

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<v Speaker 1>an hour instantly incapacitating passing prey, so it doesn't really

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<v Speaker 1>matter that conesnails are slow pokes. All the snail has

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<v Speaker 1>to do is reel its prey into its mouth. Other

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<v Speaker 1>cone snails, like the aforementioned geography cone creep up on

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<v Speaker 1>sleeping fish and shoot out a cloud of chemicals, one

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<v Speaker 1>of which is insulin that numbs their prey and sends

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<v Speaker 1>them into a sort of hypoglycemic coma before swallowing them whole.

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<v Speaker 1>Yet other cone snails will strike a fish but won't

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<v Speaker 1>tether it with their harpoon. The fish will swum away,

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<v Speaker 1>but will fall under the influence of the snail's venom

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<v Speaker 1>pretty quickly. All the snail has to do is follow

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<v Speaker 1>its prey and gobble it up. These are just a

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<v Speaker 1>few con snail strategies, but with so much diversity in

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<v Speaker 1>conesnail venom, we have a lot to learn, Safavi said.

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<v Speaker 1>We know very little about the various ways that conesnails

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<v Speaker 1>use their venom in the wild. A colleague of mine

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<v Speaker 1>recently showed that some con snails use toxins that mimic

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<v Speaker 1>mating pheromones to lure worms out of their It's really

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<v Speaker 1>fascinating what these animals are capable of. Today's episode is

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<v Speaker 1>based on the article the con snail is a slow

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<v Speaker 1>but highly venomous predator on how stuffworks dot Com, written

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<v Speaker 1>by Jesslynshields. Brain Stuff is production of iHeartRadio in partnership

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<v Speaker 1>with HowStuffWorks dot Com and as produced by Tyler Klang.

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<v Speaker 1>Four more podcasts from my heart Radio. Visit the iHeartRadio app,

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