How Does the Slow Cone Snail Catch Prey?

Cone snails move slow, but catch prey fast with harpoons or clouds of paralyzing toxins. Learn more in this episode of BrainStuff, based on this article: https://animals.howstuffworks.com/marine-life/cone-snail.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff. Lorn
Bogelbaum here. Cone snails are a group of around a
thousand species of venomous, predatory marine snails that live in
shallow tropical waters around the globe. Their pretty, cone shaped
shells are intricately patterned and brightly colored, apprized by seashell collectors,

(00:26):
and their venom is fascinating to biomedical researchers and science
fiction writers alike, a pretty high profile for a very slow,
not particularly aggressive animal that spends its days toddling after worms, fish,
and other snails for dinner. For example, In the real world,
their venom has been used in therapies from diabetes treatment

(00:47):
to terminal pain management. And this is a little bit
of a deep cut, but take the Jurassic Park film
sequel of the Lost World. In the movie, an air
gun with venom darts is used to take down Peschi dinos.
The active ingredient is purported to be an enhanced venom
from the cone snail species Conus propuis, ends, of which

(01:07):
the movie says is the most powerful neurotoxin in the world.
Before the article, this episode is based on how stuff
work spoke with Helena Safavi, an assistant professor of biochemistry
at the University of Utah who studies conesnails and their venom.
She said, in the movie, the venom is described as
the most powerful neurotoxin in the world that acts within

(01:28):
one two thousandth of a second, faster than the velocity
of nerve conduction. None of this is true, but nevertheless
very entertaining. Conesnails are very slow animals that cannot graze
on algae like their non venomous snail relatives, but also
have no means of mechanical prey capture. That is to say,

(01:49):
they can't bite or grasp like a shark or cat.
And despite the lack of teeth and claws, all cone
snails are impressive predators. Safavi said a when a slow
animal wants to hunt other creatures, it has to evolve
potent venom to be successful. Particularly those cone snails that
prey on fish have to have toxins that can potently

(02:10):
immobilize the fish prey before it swims away. One of
the most remarkable things about the thousand ish species of
cone snail is that there's almost no overlap in the
toxins that are made by each A Safavi said, this
shows how fast these toxins evolve. Even very closely related
species have only around five to ten percent overlap, with

(02:34):
each species making several hundreds of toxins. One can estimate
that there are around half a million different toxins present
in cone snails. Because their venoms are unique to specific species,
some species deliver a very minor sting and others could
kill you. A Safavi explained there are about forty known

(02:54):
fatalities by con snails, and nearly all, if not all,
were caused by a single species. Conus geographis commonly known
as the geography cone. Some of the toxins in this
species can cause acute respiratory failure and potentially heart failure.
It's also one of the species that can inject larger
quantities of venom compared to most other cone snails. Compared

(03:16):
to snakes and even scorpions and spiders, death from cone
snail stings are extremely rare. Cone snails might not have fangs,
but most have a venom covered harpoon that they use
to incapacitate their prey. Okay mollusks, like snails, often have
a radula a type of combination tooth and tongue structure.

(03:39):
It's often a ribbon like structure with many tiny teeth,
and it helps them scrape up or cut down food.
In the case of cone snails, the radula has a
venom sack at its base and it's barbed at the
other end it can dart out. It's some four hundred
miles an hour. That's about six hundred and fifty kilometers
an hour instantly incapacitating passing prey, so it doesn't really

(04:02):
matter that conesnails are slow pokes. All the snail has
to do is reel its prey into its mouth. Other
cone snails, like the aforementioned geography cone creep up on
sleeping fish and shoot out a cloud of chemicals, one
of which is insulin that numbs their prey and sends
them into a sort of hypoglycemic coma before swallowing them whole.

(04:25):
Yet other cone snails will strike a fish but won't
tether it with their harpoon. The fish will swum away,
but will fall under the influence of the snail's venom
pretty quickly. All the snail has to do is follow
its prey and gobble it up. These are just a
few con snail strategies, but with so much diversity in
conesnail venom, we have a lot to learn, Safavi said.

(04:48):
We know very little about the various ways that conesnails
use their venom in the wild. A colleague of mine
recently showed that some con snails use toxins that mimic
mating pheromones to lure worms out of their It's really
fascinating what these animals are capable of. Today's episode is

(05:09):
based on the article the con snail is a slow
but highly venomous predator on how stuffworks dot Com, written
by Jesslynshields. Brain Stuff is production of iHeartRadio in partnership
with HowStuffWorks dot Com and as produced by Tyler Klang.
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