What
are octopuses, squids and cuttlefishes?
Have you eaten a sotong? How about an octopus, perhaps at a Japanese
restaurant? So you know what it looks like.
Have you ever seen a snail? Yes, almost everyone knows what a snail
looks like. Octopus, squids and cuttlefishes are their relatives!
Octopuses, squids and cuttlefishes belong to a group of animals
called molluscs. Other molluscs include clams and slugs.
Signs of cephalopods
- Let's
looks at this cuttlebone! Cuttlebones
are commonly washed up on the shore. You can do in a shelter during
rainy weather or while waiting for the tide to go down.
- Can
you guess what this is? Cephalopod
egg capsules are sometimes seen. "Watch your step!"
Cephalopods
are special
Some special features to highlight
- Smart!
Octopuses are considered the most intelligent of animals without
backbones. They can learn tricks, even from one another.
- Jet-propulsion
they move rapidly by squirting water out.
- Masters
of disguise they can change their colours and in octopuses,
even their body texture to match their surroundings. Squids talk
to one another through colour changes.
- Disappearing
ink they can squirt ink to distract and confuse enemies. But
don't force the animal to do this.
Octopuses,
squids and cuttlefishes are important to the ecosystem
- Everyone
loves to eat sotong! Including other animals. Cephalopods
are part of the food chain. Can
we think of some animals that might eat them? Some charismatic
animals to highlight: crabs, fishes.
- As predators,
they help keep the population of their prey in check and maintain
the natural balance.
Octopuses,
squids and cuttlefishes and you
We all love to eat them!
- In
Asia, they may be eaten freshly cooked, or they may be dried.
They are also made into candied snacks.
- Other less
well known human uses include:
- In
the past, cuttlefish ink, called 'sepia', was used for writing
and painting.
- Squids
also have a role in human medical applications. Squids have
gigantic nerve cells that are relatively easy to study. Much
of what we know about our own nervous system is based on studies
of squid nerve cells. Several Nobel prizes were based on such
studies!
- The
squid's efficient jet propulsion system is also inspiring
designs for better underwater vehicles.
Cephalopod
myths to dispel
- Not all
are harmless. Some like the tiny blue-ringed octopus can kill.
But is quite rare on our shores. If you are not sure, don't touch
any octopuses.
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Handling
tips
Where to find them? They are more active at night or
near sunrise and sunset. Octopuses generally hide in holes
and it's impossible to dig one out. Squids and cuttlefishes
swim about and can be very fast. The tiny pygmy
squid is quite common, but takes a keen eye to spot.
Can't find the animals? Look for signs of them. Cuttlebones,
egg capsules are easy to talk about as they don't run away.
Don't dig up the octopus! It is almost impossible to
do so, you will be setting a bad example to visitors, and
you will be damaging the surrounding area. If you wait patiently
without splashing around, the octopus will usually go about
its usual business.
Don't try to tank an octopus. It can crawl rapidly
out of any container and move for a short distance over dry
land. If it's too far from water, however, it may die.
Don't harass them: Don't stress them to force them
to ink.
Don't handle them: Octopuses can bite and many produce
a toxin.
Don't remove egg capsules from their support! This
will kill the babies.
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