An octopus “sees” with its skin
Adapted from cbc.ca by Nancy Carson
Cover the eyes of an octopus
with your hands.
Or put a blindfold over its eyes.
It will not be blind!
Researchers studied pieces of skin
from a California two-spot octopus.
Octopus skin is different from its eyes.
The skin cannot see details.
But the skin notices changes in light.
Hiding in plain sight
Octopuses can change their colour
to look like rocks or sand.
They can change to gray, brown,
pink, blue or green.
This is called camouflage.
Enemies like sharks, eels
and dolphins swim by.
They do not notice the octopus.
No brain needed
Researchers did not test living octopuses.
They tested pieces of octopus skin.
They turned lights onto the skin.
Spots on the skin got bigger.
This made the skin look darker.
This reaction happened without
the help of the animal’s eyes.
And without the help of its brain.
A cloud of black
When an enemy discovers an octopus,
the octopus shoots a cloud of black ink
into the water.
Then the enemy cannot see the octopus.
The ink also has something in it.
This substance makes it difficult
for the enemy to smell the octopus.
The octopus can flee quickly.
Its soft body can also squeeze into
very small cracks.
Its enemies cannot follow.
If it loses an arm,
it can grow another arm.
Octopuses have a sharp beak.
So, they can give a nasty bite.
Seals, whales and large fish
will hunt octopuses.
Most octopuses stay
along the ocean floor.
Other kinds of octopus live
near the water’s surface.
Crabs, shrimp and lobsters
are some of their favourite foods.
Octopuses live alone in a protected area or den.
They can grow to 1.5 metres in length.
And they can weigh up to 10 kilograms.
Scientists say octopuses are
the most intelligent of all animals
which have no backbones.
- blindfold: a piece of cloth tied around the head
to cover someone’s eyes
- camouflage: a shape or colouring used to hide a person or thing
so that they look like their background