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All over the world, you can find venomous marine snails known as cone snails.
And unlike most land snails, which feed on plants, cone snails are carnivores.
They like to eat things like fish and burrowing worms.
The only problem with this lifestyle strategy is…that they are snails.
Chasing prey is not exactly their forte.
Fortunately for them, they’ve evolved some creative ways
to take down prey using their venom.
This stuff is deadly to fish and humans.
But surprisingly, after learning just how cone snails use their venom to hunt,
scientists have realized that certain chemicals in it
could actually be really useful for medicine.
So, these deadly snails have pointed the way
to some potentially life-saving medical innovations.
And they’ve done so in a few ways,
thanks to a few different tricks they have for catching a meal.
One way these snails hunt is with what’s called the taser and tether method.
It’s a simple strategy: When a snail detects fish nearby, it first extends
its proboscis, which is kind of like an elephant trunk for snails.
And at the end of this proboscis there’s a hollow, tooth-like structure called a radula
that pierces the fish’s skin and injects the fish with venom.
So, the proboscis is basically a cross between a harpoon and a hypodermic needle.
The radula is even barbed like a harpoon, so the fish gets caught on the end.
And thanks to the venom, it gets almost instantly paralyzed, so it doesn’t struggle
as the snail slowly reels it in, engulfs it in its body, and digests it.
As one does.
And there’s a piece of this that scientists found especially interesting.
The venom’s ability to induce rapid paralysis inspired
some researchers to investigate how exactly this venom worked.
One team found that the venom contains a short chain of amino acids,
the same molecules that make up proteins, that bind to specific receptors in fish,
quickly paralyzing them.
We humans have similar receptors, but in our bodies,
they don’t induce paralysis.
Instead, they play a key role in our pain perception.
So the researchers realized that maybe these conotoxins,
which are cone snail toxins, could help people with chronic pain.
And they actually managed to isolate one of these molecules
and make it into a therapeutic drug sold under the trade name Prialt,
which has successfully been used to treat chronic pain.
Now, while some cone snails have mastered the taser and tether method,
at least one other species has evolved to take down their prey
by releasing a cloud of venom into the water, a strategy known as net capture.
These snails’ venom contains insulin (yes, that insulin)
a hormone that regulates glucose levels in the blood.
Any fish that swims into the cloud absorbs that insulin into their body.
In seconds, its blood sugar levels plummet,
and it enters a state known as hypoglycemic shock.
Then the snail makes its move.
It slides over and engulfs the whole fish, before it can snap out of its paralysis and escape.
What researchers find especially impressive about all this
is just how fast the insulin lowers the fish’s blood sugar levels.
Now, insulin is a well-known treatment for diabetes:
People may use injections of it to lower their blood sugar.
But these treatments take time to work.
Even the fastest drugs on the market take 15 to 90 minutes to go into effect.
Meanwhile, the cone snails’ insulin seems to affect fish in a matter of seconds.
And that’s because it’s different from the stuff in our pharmaceuticals.
It evolved to rapidly bind to and activate the insulin receptors in fish,
and it may work similarly for other vertebrates too.
And we are other vertebrates.
The research is still in the early phases, but it shows promise.
If all goes well, it could be an excellent candidate for a fast-acting insulin drug
that could revolutionize the way we treat diabetes.
Now, while some cone snails hunt fish,
others prefer to eat burrowing worms known as polychaetes.
But to catch these worms, snails first have to lure them out of their holes.
And, once again, they rely on the compounds in their venom to get the job done.
One species, known as the imperial cone snail, has an especially creative strategy.
This snail synthesizes a chemical that mimics the polychaete’s sex pheromones
and releases it into the water.
Soon, the worms come out of their burrows, ready to mate.
But instead of finding themselves facing a new partner,
they find themselves facing a new predator.
To make matters worse, the worms’ bodies can’t break down
the imitation pheromones the way they would break down hormones they produce,
so they irresistibly induce the worms’ mating behaviors.
The males start releasing sperm and the females start swimming in tight circles.
Once they’re good and distracted,
the snails use their proboscis to stun their victims and…you know the rest.
But while the tactic of stunning and devouring their prey
is similar to other cone snails’ methods,
the chemicals the imperial cone snails use to trick its prey are unique.
They’re a type of lightweight compound known as small molecules,
which are naturally produced in all sorts of organisms.
And various animals’ small molecules have been used to make drugs.
For instance, the small molecules made from fire ant venom may help
treat psoriasis, while the ones produced by spiders may help treat pain.
In fact, 90% of drugs on the market, including aspirin and antihistamines,
fall under the category of “small molecules”.
So scientists are hopeful that imperial cone snails’ unique formula
may also have medical uses, although none have been explored yet.
So far, only one of the cone snails’ venomous compounds
has been adapted as pharmaceuticals, but others hold promise.
They evolved to help these snails solve a simple problem:
how to get their next meal.
But they may also be able to help us with some really complex problems
that have eluded scientists for ages, like chronic pain and diabetes.
So, the next generation of therapeutics may still be out in the ocean,
waiting to be discovered.
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