Mimic Octopus: The Great Impersonator

Photo: Mimic Octopus pretending to be a mollusc

What is a Mimic Octopus?

The mimic octopus is a master of disguise. This small eight-armed cephalopod can change its colours and contort its body to impersonate over 15 highly toxic, dangerous and bad-tasting marine animals, including venomous predators like lionfish, sea snakes, and jellyfish. It can quickly switch between disguises and can even change disguises while moving. The scientific name for the mimic octopus is Thaumoctopus mimicus, roughly translating to miraculous eight-footed mimic. It was only discovered in 1998, near a muddy river mouth off the coast of Sulawesi, Indonesia.

Mimic Octopus Description & Appearance What does a Mimic Octopus Look Like?

The mimic octopus grows to about 60cm in length from the tip of its arms to its head. It has a globular head with short horns protruding over each of its two eyes. Its natural colouring is light brown/beige, which helps it blend easily with its muddy seafloor environment. However, it can take on many other shades, patterns, and forms to scare off predators.

Mimic Octopus has 9 Brains!

The mimic octopus has nine brains. Each of its eight arms has a mini-brain, and it has a centralised brain in its head. Each of its eight arms can taste, touch, and move independently. At the same time, the centralised brain can override and directly control the octopus's body as required.

Mimic Octopus has Blue Blood

The octopus has blue blood. This is because it uses a protein called haemocyanin to carry oxygen around its body. Haemocyanin contains copper rather than iron, like we have in our haemoglobin. It also has three hearts. One heart circulates blood around its body, and the other two hearts pump blood through its gills to oxygenate its blood.

Mimic Octopus Behaviour Mimicry and Impersonation

The mimic octopus is a master of disguise and is so confident of its disguises that it forages for food during the day in full view of its predators.

For example, to mimic a banded sea snake, the octopus tucks itself into a hole and sticks out two arms displaying black bands, and wriggles them about to replicate a sea snake's movement. It imitates a Sole flatfish by flattening its body and pulling its arms flush against its body to resemble this poisonous flatfish.

The mimic octopus has even been observed moving away from danger by lifting up six of its arms and walking away on the other two as though they were legs.

Mimic Octopus Intelligence How Smart is a Mimic Octopus?

The mimic octopus is a very intelligent animal. It has nine brains; one in each arm and one centralised brain in its head.

While all octopuses can change their skin colour and texture to camouflage themselves against predators, the mimic octopus takes this capability to a whole new level. It is so intelligent that it will decide which disguise will be most effective against a particular predator. So, for example, if a damselfish attacks the mimic octopus, it immediately impersonates a banded sea snake, a deadly predator of damselfish.

Mimic Octopus Habitat Where Does a Mimic Octopus Live?

The mimic octopus lives in the Great Barrier Reef, Australia, the Indo-Pacific, and other warmer parts of the world. It prefers shallow, murky waters at depths of less than 15m with muddy seafloors, such as near river mouths and estuaries, where it can easily blend in with its surroundings.

It often shelters in the burrows of other animals. It may visit a number of these burrows within its home range. The mimic octopus is active during the day. At nightfall, it occupies the first available burrow it can find.

Mimic Octopus Diet What does a Mimic Octopus Eat?

The mimic octopus is a daylight hunter/forager that eats worms, crustaceans, and small fish. It also indulges in cannibalism. This cannibalistic tendency is believed to be more about territory than as a food source.

When hunting for crustaceans and fish, it shoots a jet of water through its funnel to propel itself over the seafloor while searching for prey. When foraging, it reaches into crevices in coral or holes in the sand, grabs its prey with the suction cups on its arms, extracts them, and eats them. It may even approach a group of crabs by pretending to be one of them, sneak up close, and pounce on an unsuspecting victim.

It is also unique among octopuses. It has been observed entering a tunnel completely and emerging from another hole up to 1m from the entrance point, searching for food. No other octopus does this.

Great Barrier Reef Animals and Plants

Mimic Octopus Reproduction Mimic Octopus Babies

When mating, the male will use its mating arms, called a hectocotylus, to place a sperm sac into the female's body. The male will die a few months after mating.

The female will carry the sperm sac in her body until she is ready to lay her eggs. At this time, she will use the sperm stored in the sperm sac to fertilize her eggs, which she will lay in long strings with the eggs enclosed within them. She will carry these strings of eggs tucked under an arm until they are ready to hatch. When the eggs are about to hatch, the female will die.

Young mimic octopuses have to fend for themselves from the moment they hatch. The male grows to significantly smaller in size than the female. It weighs about 0.5 kg. The mimic octopus has a lifespan of about 9 months.

Mimic Octopus Predators and Threats What Kills and Eats Mimic Octopuses?

The mimic octopus is eaten by large bony fishes, sea snakes and sharks. Mimic octopuses are also impacted by water pollution and habitat destruction. However, they are not considered to be endangered.

Mimic Octopus Video See the Great Impersonator at Work

An excellent video. Worth watching.