World_of_Animals_Issue_46_2017

Extreme snails
Deadliest
Cone snails pump prey with poison
Even humans fear this predator, which is known by scuba divers as an animal to avoid at all costs
The problem this species faces is simple – it’s
a slow-moving snail that eats fast-swimming
fish and needs to be able to catch prey without
expending too much energy. A high-speed
chase is out of the question, but thankfully for
this snail it has a lethal trick in its shell. During
its evolution it developed a weapon that allows
it to kill anything that gets too close.
Cone snails can modify
their venom to create
different lethal cocktails
to stun a variety of prey
Tucked beneath its speckled shell is a
harpoon filled with venom for which there is no
antidote. The fluid inside is so toxic that fish are
paralysed instantly, allowing the cone snail to
eat a meal without having to move. In fact, it’s
potent enough to take down an adult human,
and this snail alone is responsible for more than
30 fatalities to date.
This is not only the world’s deadliest snail;
it’s one of the most venomous animals alive.
Researchers are working to pick apart the
hundreds of chemicals that make up its venom
and have found proteins that are 10,000 times
more effective than morphine as a painkiller. It
also contains a form of insulin that causes the
blood sugar of prey to drop to a fatal level.
How it hunts
This static sharpshooter sits and waits for prey
Proboscis
Toxic
harpoon
The waiting game
With an arsenal of deadly poison ready to fire, the
cone snail stays in the same place waiting for prey
to cross its path. It even waves its long proboscis to
lure fish into the danger zone.
Harpoon action
Once prey is in range the snail throws out a hollow,
modified tooth that contains the fatal cocktail. The
fish will become motionless in less than a second,
saving the snail from having to pursue its meal.
Down in one
Stretching its mouthparts wide, the snail swallows
the fish whole; the venom has no effect on the snail.
It can wolf down animals that are equal in size to it,
and only the prey’s bones are excreted.
Violet sea snails
are pelagic (Greek
for ‘open sea’),
meaning they
drift along on the
ocean surface
Cleverest
Violet sea snails sail the oceans
While it’s impossible to determine how intelligent a snail is, this specimen
definitely tops the charts for being the most enterprising
This snail forms a buoyant raft at the
entrance of its shell by inflating bubbles of
mucus. It’s the pirate of the snail world and
spends its entire life floating at the ocean’s
surface feeding on venomous animals like
the Portuguese man of war jellyfish.
Interestingly, all violet sea snails are born
male and mature into females as they age.
Male snails release a case of sperm into the
water, which drifts towards a female who
can then use it to fertilise her eggs.
Everything in this animal’s life is
precarious, from the raft that prevents
it sinking to certain death to predators
seeking a meal. Its purple colouration
helps the shell stay hidden using a type
of camouflage called countershading. The
dark base faces upwards and blends in
with the sea when viewed from above,
while the tip of the shell that hangs upside
down is light in colour, making it hard to
distinguish from the sky if seen from below.
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