An Octopus Impersonates a Cast of Species

Sept. 4, 2001 -- A sea creature known as "mimic" has shown researchers it's an octopus of many talents.

Biologists have observed this eight-limbed, 24-inch-long invertebrate impersonating a cast of other marine creatures.

The octopus, which lives on muddy ocean bottoms off the coasts of Bali and Indonesia, has never been observed before, so it isn't yet named. But already, the cephalopod has created quite a stir among zoologists.

"There's really no other animal that mimics more than one organism or that can switch between impersonations," says Tom Tregenza, a zoologist at the University of Leeds in the U.K. "This is quite a unique ability."

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Some of the octopus' repertoire includes:

The sea snake — a highly poisonous reptile that attacks fish. To "become" a sea snake, the octopus changes its coloring to match the yellow and black banding of the snake. It tucks its body and all but two of its limbs into a small hole in the ocean floor. Then, like a puppet master behind a screen, it waves its two exposed tentacles in opposite directions, mimicking the motion of two individual snakes.

The sole fish — a flat, oval-shaped, fish that is often poisonous. After building up speed using jet propulsion, the octopus draws all eight appendages into a leaf-shaped wedge and undulates, moving much the way a sole fish swims. It changes its color to match the drab banded brown coloring of the sole.

And the lion-fish — a nocturnal fish with an array of feather-like poisonous fins. To match this gaudy species, the octopus turns a bright blue and swims with its eight legs flared in the same way a lion fish's fins are splayed.

In a report in the September issue of Proceedings of the Royal Society of London B., Tregenza and his coauthors, Mark Norman of the Melbourne Museum in Australia and Julian Finn, of Australia's University of Tasmania noted that the octopus appears to imitate other sea creatures as well, but these three were the most distinctive.