During research dives in Indonesia by Mark Norman of the University of Melbourne in Australia, dynamic mimicry (the ability to rapidly switch between mimicking different models) was observed in a spectacular long-armed octopus new to science. The Mimic Octopus emerges during daylight hours to forage on sand and mud in full view of passing predatory fishes. Its defense is taking on the guise of other animals occurring in this habitat, particularly those armed with poisons or toxicity.
Mimicry of poisonous flatfish, banded sea snakes, lionfish and jellyfish are reported. This octopus combines color and texture changes with postures and body movements to impersonate its models; e.g. banded sea snakes are impersonated by probing six arms down a burrow and raising two undulating banded arms.
Uniquely, the mimic octopus can rapidly swap between "impersonations" as the perceived threat changes. Unique foraging behavior was also observed with the octopus foraging through subterranean tunnels up to 1 meter long.
Two potential benefits from this spectacular behavior are suggested: dynamic mimicry decreases the frequency with which predators encounter particular mimics, making it harder for them to spot imposters; and it allows the octopus to use the most appropriate form of mimicry for a particular threat.
(Reference: Dynamic mimicry in an Indo-Malayan octopus, by M. D. Norman, J. Finn & T. Tregenza. The Royal Society Proceedings B Vol. 268, No. 1478 Pg 1755)
(Editor's Note: This paper puts into context and builds on images first seen in the BBC/Discovery 2000 natural history documentary, The Octopus Hunter, about the work of Mark Norman of the University of Melbourne in Australia, the original octopus hunter.)
[Contact: Mark Norman, Tom Treganza]
29-Aug-2001
