Mimic octopus

The mimic octopus (Thaumoctopus mimicus) is a species of octopus from the Indo-Pacific region. Like other octopuses, it uses its chromatophores to disguise itself. It is noteworthy for being able to impersonate a wide variety of other marine animals.^[2] While many animals mimic either their environment or other animals to avoid predation, the mimic octopus and its close relative the wunderpus are the only ones known to actively imitate several animals in order to elude predators.^[3]

The mimic octopus is a smaller octopus, growing to a total length of about 60 cm (2 ft), including arms, with a diameter approximately that of a pencil at their widest. Small horns protrude from each eye. The octopus' natural color is light brown/beige, but it usually takes on a more noticeable hue of striped white and brown to scare off predators by imitating poisonous species. According to DNA sequence analysis, the second evolved trait was the simultaneous development of its lengthy arms and its flatfish-like swimming ability. By transfusing these traits together, the octopus transforms to a bold color pattern while swimming like a flatfish when hunting for food or resting.^[4]

The mimic octopus was first discovered off the coast of Sulawesi, Indonesia in 1998 on the bottom of a muddy river mouth.^[5][6] It has since been found to inhabit the Indo-Pacific, ranging from the Red Sea and Gulf of Oman in the west to New Caledonia in the east, and Gulf of Thailand and the Philippines in the north to the Great Barrier Reef in south.^[1][7][8] Most documented observations are from Indonesia.^[7] It is primarily found in areas with sand or silt at depths of less than 15 m (49 ft).^[2] It prefers obscuring murky and muddy sea floors to blend in with its natural brown-beige coloring.

The mimic octopus uses a jet of water through its funnel to glide over the sand while searching for prey, which mostly consists of small fish, crabs, and worms. It prefers river mouths and estuaries, as opposed to reefs which are usually preferred as shelter by other types of octopus.

Mimic octopuses have been observed mimicking numerous different species of animals, some animals being mimicked more often than others. Among the animals mimicked are lionfish (the octopus holds its arms out radially to mimic the fish's spines), sea snake (hiding 6 of its arms, it holds the remaining 2 parallel to each other),^[9] jellyfish (by inflating its mantle and trailing its arms behind it), and zebra sole (holding all 8 arms behind it as it uses its siphon to swim). The octopus' mimicry of flatfish may be its preferred guise; a 2008 study showed that over a period of 5 days, nearly 500 instances of flatfish mimicry were seen by a single individual.^[10] Not only does the mimic octopus use its ability to defend from predators, it also uses aggressive mimicry to approach wary prey, for example mimicking a crab as an apparent mate.

The mimic octopus retains the ability to camouflage with its sandy environment. It was also observed to mimic sessile animals such as small sponges, tube worm tubes, or colonial tunicates.^[10]

The octopus may be able to intelligently use its mimicry based on the situation. For example, a mimic octopus which was being harassed by damselfish mimicked a banded sea snake, a known damselfish predator.^[11] The mimic octopus has also been observed in opportunistic mimicry with a jawfish.^[12]

The mimic octopus can either be classified as a hunter or a forager. It is believed to be a hunter because scientists have observed and recorded the octopus having the ability to stalk prey and hunt down small fish and catch them. More often, however, the mimic octopus can be seen foraging for food. It does this by using a jet of water through its siphon to glide over the sand while searching for prey, and using its slender arms to reach into crevices in coral, as well as holes in the sand, and use its suction cups to grab small crustaceans and eat them. Because the mimic octopus prefers to live in shallow, murky waters, it is believed that its diet consists almost exclusively of small fish and crustaceans. They are believed to be carnivores, and are not known to eat any type of plant or vegetation.^[2]

• Butvill, David B (7 October 2005). "The Changeling". Current Science.
• Hearst, M.; Noordeman, J (2012). Unusual creatures: A mostly accurate account of some of the Earth's strangest animals. San Francisco: Chronicle Books: Chronicle Books. ISBN 978-1-4521-0467-6. [children's book]
• PZ Myers (29 November 2004). "Indo-Malayan mimic octopus". Pharyngula. Archived from the original on September 16, 2008.
• Norman, Mark. "Masters of Mimicry". Nature Australia. Vol. 27, no. 6 (Spring 2002 ed.). Australian Museum. Trust. p. 38.