How a cone snail kills its prey

Dif­fer­ent species hunt dif­fer­ent kinds of food, but they all pack a lethal punch.

Popular Science - - THE BIGS - By Anna Brooks

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Tar­get Conus catus hunts fish by ex­tend­ing a pro­boscis, a sort of fleshy har­poon, un­til it feels the crea­ture’s lat­eral line—a sen­sory or­gan that helps the fish nav­i­gate. If the mol­lusk hits this nerve­filled tar­get, the vic­tim will have al­most no chance of es­cape.

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Strike Once it iden­ti­fies its mark, the tiny as­sas­sin shoots a hol­low, barbed tooth out of its pro­boscis, spear­ing the fish’s un­der­belly and se­curely hook­ing into its flesh. The now-stung quarry, thrash­ing and strug­gling to es­cape, is firmly teth­ered to the im­mo­bile hunter.

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In­ject The snail’s hol­low tooth acts as a sy­ringe, in­ject­ing tox­ins into the prey. This venom con­tains hun­dreds of pep­tides that work in tan­dem. First, neu­ro­tox­ins stop the vic­tim’s nerve im­pulses from switch­ing off, mak­ing it about as stiff as a frozen fish stick.

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Eat A se­cond set of pep­tides stops the nerves from com­mu­ni­cat­ing with mus­cles. Within 20 min­utes, the fish goes limp. This serves as a backup: If the fish shakes off the rigid paral­y­sis and es­capes, the snail can search for and con­sume its im­mo­bi­lized prey.

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Di­gest As tox­ins do their work, the preda­tor reels the vic­tim into its mouth. Di­ges­tion starts while the fish is alive. An hour or so later, the snail re­gur­gi­tates scales, bones, and the har­poon. More barbs, formed within a quiv­er­like or­gan, await the next vic­tim.

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