Cone snails may look harmless, but they are some of the most dangerous animals on Earth. In the ocean, they use their venom to hunt and protect themselves from predators.
Textile cone snails, which are well camouflaged in the sand, hide and wait until their prey is within striking distance before unleashing their remarkable weapon, a modified tooth, or “radula,” which forms a spear-like projectile that they can use to introduce a buffet of nastiness.
All cone snails are poisonous, but each species produces its own unique blend of toxins that have evolved to target specific prey; larger species go after small fish, while smaller species tend to prey on worms.
However, the venom of cone snails not only paralyzes prey, but can also kill humans. It is estimated that the venom of one of the deadliest cone snails can kill up to 700 people.
Studies have also shown that the venom of cone snails contains large amounts of a unique form of the hormone insulin, which is used throughout the animal kingdom to regulate metabolism by helping to remove excess glucose from the blood. The insulin in the venom was not the kind that these predatory clams use to regulate their own blood sugar, and was actually more similar to that found in their prey, fish. Also, it was only present in cone snails that prey on fish, not in the smaller ones that prey on things like worms.
When the researchers directly injected this version of insulin into the danio fish, their blood sugar plummeted and they went into hypoglycemic shock. But when they added it to their water, they immediately went into a stupor and started swimming much slower. So the researchers speculate that the two species calm their prey by giving them an overdose of insulin.
Although cone snails are not the most famous venomous animals, they are a serious threat to humans. So if you see a cone snail on the beach or in the ocean, it’s best not to get close to it and don’t touch it.
