That’s a really interesting question. Obviously
they do release ink clouds, but is it an
instinct or can they control it? I don’t have
a final answer for you, but I discovered some
really cool things.
First, squid can release different kinds of ink
clouds. One kind is just a big cloud that seems
to act as a smoke screen to hide the squid.
The other kind is denser and about the size of
a squid. It may distract inexperienced
predators, sort of like a fake out, or the scene
in a movie when the villain is using a hologram or
a mirror. In order for the squid to use the right
kind of ink cloud, it stands to reason that they
would have to decide, not just have an instinct
like “get scared, squirt ink.” So it seems
logical that they have some control. To really
know, we’d have to do (or find) an actual
I found a really interesting experiment on another
escape mechanism that squid have. Normally, they
move by swimming forward with fins. When
attacked, they send a jet of water through their
“funnel.” This shoots them backwards quickly.
Researchers wanted to know whether this was just a
reflex or under the control of the squid.
First, they had observations. Even newly
hatched squid jet backwards if something is
coming at them quickly. They can do this before
they have a chance to really learn anything, so
it’s at least partly a reflex, like ducking when
something is coming toward your head. That makes
sense because if you have to learn to avoid
predators, you’ll probably get eaten before you
Another observation was that newly hatched
squid are on their own to catch food. They start
off pretty bad at it, but learn to be better by
trial and error. They can jump at slow prey,
but for fast prey, they need to stay still with
their arms and tentacles out and catch the prey as
it swims by. At first, as soon as they start to
catch the prey, the squids have the jet backwards
reflex, so they fail to catch prey. Later they
seem to control that reflex, like you can make
yourself not flinch when a ball is thrown at you.
To see if the squid were actually learning to
control their response (and it just wasn’t fading
as they got older), they raised a bunch of squid
from eggs. Half were raised with fast prey. They
learned to not jet away when they caught the prey.
Half were raised with slow prey that could be
jumped at, and most never used the sit-and-wait
strategy. Then they took the squid raised on slow
prey and gave them only fast prey. Even when they
used the sit-and-wait strategy, they couldn’t stop
themselves from jetting away from their prey. This
is evidence that
1. Squid learn to control the response
(it doesn’t just fade with age).
2. If they don’t learn to control it early, they
may not be able to control it later.
So the answer is that it’s probably an
instinct, but also something that they can
learn to control with practice if they start
learning early enough.
Why did the researchers need to use two
groups of squid? Why not just look at how squid
hunted fast prey? Why not just raise the squid on
slow prey, then switch them to fast prey? What
experiment would you do next?
Thanks for asking,
Coleoid cephalopods (squid, octopus,
cuttlefish) have ink that they release when
alarmed or startled.
By observing their behavior and how they do
this, we can tell that it is pretty
instinctual, but they release ink at times other
than being attacked. A sudden vibration in
the water can cause them to release ink, something
to be alarmed at but not necessarily an attack.
Nautiloid cephalopods I do not believe have
ink sacs, and so cannot release ink clouds.
Thanks for the great question!
All known cephalopods, except for the nautilus
and a type of octopus, have an organ called the
ink sac, which releases a cloud of dark ink
used to confuse predators . The ink is a
chemical pigment called melanin, which also
happens to be what gives human skin its color.
The ink is released when the cephalopod is
threatened or scared by something, and so, yes, is
done so instinctually.
The ink is used as a kind of smokescreen is used
to hide where the cephalopod when a predator comes
near. It can get more complicated even. Often
the ink is mixed with mucus by the cephalopod,
which gives the ink a more defined shape, a shape
that can almost look like the cephalopod!
This decoy is used to draw predators away from the
cephalopod. Also, cephalopods use this behavior to
not only protect themselves, but to also to
protect their eggs.
Cephalapods such as squids, octopuses, and
cuttlefish are known to squirt ink at predators
for protection. As a side note, I would avoid
saying they know they “are about to die” since the
concept of death is a high-level concept which has
generally only been observed in mammals.
The cephalopod simply knows it’s in danger
and instinctually responds to the danger.
Instinct refers to unlearned behavior and there is
no evidence to suggest that cephalopods are taught
to squirt ink. Therefore, it is reasonable to
conclude that the release of an ink cloud is an
instinctual response. Cephalopod ink is
mostly made of melanin which is the same
molecule that gives our skin and eyes color. It
can distract a predator and can even mess with the
predator’s sense of smell, giving the cephalopod
time to escape. In some cases, the ink is mixed
with a lot of mucus to create a “fake
cephalopod” which the predator
mistakes as a real animal.
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