While all other octopus species change their appearance to blend into the background, the mimic octopus is the only animal that can pretend to be specific animals
Even more impressively, it is the first species found to mimic more than one species of poisonous animal to avoid predators. It was only discovered in 1998, but it’s not surprising that it stayed hidden for so long. This clever octopus takes on the shape of different dangerous animal according to what is threatening it, so it will take on the appearance of an animal from which its attacker would flee. Scientists are still working hard to unlock the secrets of the mimic octopus, but what they have found so far is almost beyond belief.
What it mimics
If disturbed, the mimic octopus will fold its body into a leaf-shaped wedge and swim away along the seabed in a similar fashion to the banded sole. This toxic fish is a perfect camouflage for the zooming octopus as it makes its escape.
The venom-filled warning spines of the lionfish are mirrored by the mimic octopus as it swims with each of its arms spread in front of its body. The venom of the lionfish is purely defensive, so it is a great fish to mimic to repel all sorts of predators.
To act as the banded sea snake the octopus hides its head and six of its arms in a burrow, waving the remaining two high above its head. In response to an attack by damselfish, the mimic octopus will take on its reptilian disguise as sea snakes are known damselfish predators.
How octopuses change their appearance
Octopuses have pigment sacs in their skin called chromatophores. These are linked to the visual part of the brain and can be changed at will. These sacs can expand to 50 times their size and as they change size they change the colour of the animal’s skin.
Muscles at the skin surface control the texture and appearance of the skin from smooth to spiny. This helps octopuses match their background perfectly and become almost impossible to detect. If all else fails, the octopus can swim away and release a cloud of ink to cover its escape.
Some octopus species have reflective cells embedded in the skin that reflect the deep blue light of the ocean. The blue-ringed octopus is only the size of a human hand but the vivid blue rings warn predators of the deadly venom the octopus is capable of releasing.
As well as being the only animal to mimic lots of different others, the mimic octopus uses completely unique hunting techniques that have never been seen before.
The mimic octopus reaches its arms down burrows in search of food, such as shrimp and small fish. This behaviour has never been witnessed in an octopus before, and gives researchers a clue about how intelligent this animal really is.
The mimic octopus was spotted entering underwater burrows and emerging metres away by digging itself a tunnel beneath the sand. This is an extremely efficient strategy to comb a patch of sand for small crustaceans.
Image from flickr.com/photos/pacificklaus