Science

Amazing video shows how squid change colour to camouflage themselves from predators

You’ve got to be squidding me! Amazing video shows squid changing COLOUR to camouflage itself from predators for the first time – just like octopuses

  • Many cephalopods including octopuses and cuttlefish use camouflage
  • This led researchers to question whether squid also display this ability
  • While cleaning their tank, the team observedthe squid changing colours
  • When they were over algae, the squid appeared dark green, but when they were against the clean tank, they changed to a lighter shade

From chameleons to octopuses, many animals are famous for their use of camouflage to hide from predators.

Now, squid have been caught on camera employing the same techniques for the first time.

Researchers from the Okinawa Institute of Science and Technology Graduate University spotted a species of oval squid changing colour to blend in with its background when it sensed a predator might be nearby.

‘This effect really is striking. I am still surprised that nobody has noticed this ability before us,’ said Dr Zdenek Lajbner, first author of the study.

‘It shows just how little we know about these wonderful animals.’

Researchers from the Okinawa Institute of Science and Technology Graduate University spotted a species of oval squid changing colour to blend in with its background when it sensed a predator might be nearby

Camouflage in the animal kingdom 

Many animals have evolved methods of camouflage, making it hard for predators (or prey) to spot them. 

A common example is the snowshoe hare, which is a brilliant white colour to blend in with its snowy surroundings. The animal has the remarkable ability to develop a different coloured fur in the summer, to blend in with the changing terrain.

Stick insects developed a different method, changing their shape to resemble their habitat – twigs.

Octopuses can change both their colour and texture to blend in with the sea bed and rocky outcrops. 

Predators have got in on the act too, with the stripes of a tiger and the sandy hues of a lion helping them to blend in with forest and grassland, respectively.

Many cephalopods including octopuses and cuttlefish use camouflage, which led the researchers to question whether squid also display this ability.

‘Squid usually hover in the open ocean but we wanted to find out what happens when they move a bit closer to a coral reef or if they’re chased by a predator to the ocean floor,’ explained Dr Ryuta Nakajima, one of the lead researchers.

Since 2017, the researchers have been culturing a species of oval squid known locally as Shiro-ika at their research facility in Okinawa.

While cleaning their tank to remove algae, the researchers accidentally observed the squid changing colour.

When they were over the algae, the squid appeared dark green, but when they were against the clean tank, they changed to a lighter shade.

Following their initial observation, the researchers performed a controlled experiment to verify their findings.

Several squid were kept in a tank while half was cleaned, and the other half was left covered in algae.

An underwater camera was placed inside the tank, while a regular camera was suspended above it, allowing them to film the animals from two angles.

The footage confirmed their initial observations – when the squid were on the clean side, they were a light colour, but quickly became darker when they were above the algae.

While cleaning their tank to remove algae, the researchers accidentally observed the squid changing colour

While cleaning their tank to remove algae, the researchers accidentally observed the squid changing colour

When they were over the algae, the squid appeared dark green, but when they were against the clean tank, they changed to a lighter shade

When they were over the algae, the squid appeared dark green, but when they were against the clean tank, they changed to a lighter shade

While the findings are exciting, in that they mark the first time squid have been seen camouflaging, they could also have important implications for coral reefs, according to the researchers.

‘If substrate is important for squid to avoid predation then that indicates that increases or decreases in squid populations are even more tied to the health of coral reef than we thought,’ explained Dr Nakajima.

The team now hopes to study squid further to understand more about their camouflaging abilities.

Professor Jonathan Miller, senior author of the study, concluded: ‘We look forward to continuing to explore the camouflage capabilities of this species and cephalopods more generally.’

CAMOUFLAGE TECHNIQUES USED BY BOTH PLANTS AND ANIMALS

Plants may appear passive but they camouflage themselves just like animals, research has revealed.

Blending into the background helps plants protect themselves from predators and has the same benefits as the technique does to animals.

They use various crafty techniques including making themselves look like unimportant objects such as a stones.

Background matching – this involves blending with the colours of shapes of the habitat where they live.

Disruptive coloration – markings that create the appearance of false edges and boundaries, making it harder to see the true outline.

Masquerade – looking like something else; usually something a predator might ignore, such a stone or twig. 

Examples include living stones, some cacti, passion vines and mistletoes.

Decoration – accumulating material from the environment. 

For example, some coastal and dune plants get covered by sand because of their sticky glands, making them less conspicuous of shapes of the habitat where they live.

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