- Hello guys and girls, I'm Reefman
and today we're going to talk about snails.
Snails that hunt and eat fish
and other animals, cone snails.
Cone snails are members of the genus Conus,
and they make up the largest genus of animals in the sea
with over 800 species.
Work has been done recently to split up the genus
but nothing's been finalized as of 2019.
We've all heard of cone snails
and at least 141 human envenomations
have been reported and confirmed over the past 350 years.
Of which 36 were fatal.
The true number of stings is likely to be higher though
as they tend to happen in remote locations
away from medicine and news organizations.
Cone snails show up in aquariums every now and then
so it's a good idea to know a little bit about them
and what they look like.
When they're in your tank,
they almost always arrive with a shipment of other snails.
Since they're carnivorous,
they won't do much for your clean up crew
other than perhaps eating it.
They range in size from a fingernail
up to several inches long
with the fish eating varieties
like the Conus geographus here
being larger than the species that eat snails and worms
like the Conus textile here.
As their name would suggest,
all cone snails have roughly cone shaped shells
with their proboscis and eyes at the smaller end.
The ones that eat fish
are often found under sand, like a Fighting Conch,
waiting for a fish to come along.
The species that eat worms or snails,
they spend their time on top of the sand
where their pray is found
and their shell could be covered in algae.
Cone snails are found throughout the world
from the temperate waters from California
all the way to South Africa
and then all around the globe
around the topical waters in the Indo-Pacific
where our corals and fish are commonly found.
The largest variety of them,
with over 700 species, are found in the Indo-Pacific ocean
from about Indonesia to Australia
and then maybe out to Hawaii.
So what should you do
if you think you might have a cone snail
in the group of snails that you just got?
It does happen.
So what do you do?
The most likely type of cone snail
that you could encounter in the aquarium trade by mistake
will only really be able to sting you about as bad as a bee
unless you're allergic
but it's still best not to grab it with your hands,
even if you just suspect it might be a cone snail.
Use tongs or a kitty litter scooper,
something like that to remove it from the tank.
Put it in something like a clear glass bowl
or a quarantine tank
and you'll be able to get photos.
Take some photos of the top
and also the bottom of the snail
and then post them online like REEF2REEF
or something like that
and people will help you identify
exactly what it is.
You can tell what kind of food a cone snail eats
by looking at the bottom of its shell.
This can help with identification.
A large, wide opening means it most likely eats fish,
while smaller, narrower openings indicate
a worm or some other snail would be the food.
Fish eating cone snails are far more dangerous to humans
than those that eat snails or worms
because obviously a fish can get away
whereas a snail can't,
so this kind of a snail needs a far more potent a venom.
Fish eating snails eat by expanding a membrane out
and around their target fish while it sleeps
and then after they envelop the fish,
they use a hollow barbed tooth,
which is actually called the radula,
to inject their venom
and then that venom paralyzes the fish
before it can get away
and then the snail eats it.
Cone snails can fire more than one radula
in a single hunting session
and people have been stung up to three times
after picking up a snail.
It's also possible for a fish
to simply get too close to a snail
where it's hiding and then they're very opportunistic
and so they've been known to actually envenomate
and paralyze fish that are just far too large
for a snail to eat.
They can eat fish about as long as their shell though.
There are two species of cone snail,
Conus geographica and Conus tulipa which I have here
and both of these make a chemical very similar to insulin
in their venom and this actually puts their fish
into hyperglycemic or hypoglycemic shock
in the same way a human would be in shock
if they were to overdose on insulin.
These are the only two animals that we know of
that use insulin in venom like this.
Cone snail venom has also been made into medicine
that you can get today from your doctor
as a painkiller called Ziconotide or PRIALT.
These drugs actually block calcium channels in nerve cells
and then they block the nerve cell's ability
to transmit pain signals to your spinal column
and then they are a painkiller because of that.
Conotoxin research is ongoing
because it's found that, for example,
that kind is about 10,000 times more powerful than morphine
and it's not addictive the way morphine is
which makes it a great drug.
Conus geographica eats only fish
and is the largest member of the Conus genus.
It's very likely that all human fatalities
are attributable to this single species.
This species is very common in the wild
throughout the whole Indo-Pacific ocean
and is collected in some places for its shell.
While it may not seem possible,
this fish, as well as other fish eating species,
like tulipa, can eat a fish the length of their shell
or maybe even a little bit longer than the shell.
Conus textile is found throughout the Pacific Ocean,
all the way to Hawaii and is dangerously venomous
although it eats snails.
In the wild, this species feeds on snails
and things like that, other molluscs and gastropods,
taking its time when feeding
and it can actually inject its radula and its prey
10, 12 times before it's done eating
and then it goes back under the sand
and digests its meal.
Cone snails that eat snails like this,
they have venom that breaks down the bond
between the snail's shell and its body
which makes it a lot easier for the cone snail
to just sort of pull the other snail out of its shell
before eating it.
(upbeat music)
Thank you for watching.
Thanks for taking the time.
I hope you found this interesting.
Let me know what you thought in the comments
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and the creatures we find in them.
Bye.