Snails that harpoon fish

Cone snails can be much more dangerous than they look. NOAA.

Some cone snails are armed with deadly projectiles that resemble harpoons, which they use to catch fish and other prey, and also for defense.

These snails are slow moving somewhat shy creatures that tend to hide in holes and crevices, emerging at dawn and dusk to hunt. As they creep along searching for a meal, their siphon can pick up the scent of prey and their eyes on stalks can see it, so they extend their tube-like proboscis, which can reach more than twice the length of their body, towards its potential victim.

When close enough, they use their proboscis like a blowgun, shooting out a venom-loaded harpoon at about four-hundred-miles per hour (650 km/h)—more than half the speed of sound and a whole lot faster than a Lamborghini at maximum speed. The venom paralyzes the fish, while the snail reloads another harpoon from its cache. The cone snail then reels in a cord attached to the harpoon and pulls the fish into its mouth where its radula scrapes away at it. Sometimes the prey is too large for the snail to pull into its shell, so it scrapes away outside its shell. Several hours later it spits out the bones and scales.

There are many different kinds of cone snails and they tend to specialize in one specific prey, such as worms, clams, or other snails. In some, the tip of their proboscis has many tiny tentacles for sensing prey and tiny teeth for boring through the shells of bivalves.

Cone snails can sneak up on fish. Baldomero Olivera, NIH.

Some cone snails that don’t have harpoons will sedate fish by blowing wafts of toxin into the water, or they will sneak up on sleeping fish and envelop it with their tentacle-lined net-like proboscis and smother it. Occasionally they can catch a group of small fish all at once. If the snail has harpoons, it will then shoot one into each of the fish so they can’t escape.

These poisons can vary from species to species and from individual to individual. Sometimes each individual mixes its own poisons for various uses as needed. Their harpoons are filled with venom ahead of time and stored. Each is only used once. They are less than half-an-inch long, but the poisons can be extremely toxic—some of the deadliest in the world—and some can kill you with hours, but their shells are highly valued by collectors.

 

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