The mimic octopus was not described by science until 1998, despite living in the shallow coastal waters of the Indo-Pacific where divers had been working for decades. The reason it went unnoticed for so long is the same reason it survives. It looks like something else.
Researcher Mark Norman at Museum Victoria in Melbourne was the first to document the mimic octopus systematically, publishing observations of an octopus that was not simply changing color to match its background but actively impersonating the body shapes, movements, and behaviors of other specific animals. The species it was observed mimicking included the flatfish, the lionfish, and the banded sea snake, each of which is either venomous, toxic, or dangerous to the predators that would otherwise eat an octopus.
Table of Contents
What made the mimic octopus scientifically significant beyond the mimicry itself was the apparent selectivity of the impersonations. Norman and colleagues observed that when the octopus was approached by damselfish, which are preyed upon by banded sea snakes, it preferentially adopted the sea snake impersonation. The octopus appeared to be matching the impersonation to the specific predator’s known enemy.
This level of behavioral flexibility requires the octopus to recognize the species of the approaching predator, retrieve the appropriate impersonation from a repertoire of multiple options, and execute a body posture and movement pattern that convincingly resembles a different animal. Each of these steps involves cognitive processing that researchers are still working to fully characterize.
The Mimic Octopus’s Mechanics of Impersonation
The flatfish impersonation involves the octopus flattening its body, drawing its arms together in front and behind, and undulating across the seafloor in a motion that closely resembles the swimming pattern of a flatfish. The lionfish impersonation involves spreading the arms to resemble the venomous spines of the lionfish while hovering in the water column. The sea snake impersonation involves burying six arms in the sand and extending two arms in opposite directions, striped with the banding pattern of a sea snake. Each impersonation requires a different body configuration, a different movement pattern, and a different color display. The octopus switches between them in response to changing circumstances, sometimes mid-encounter.
The Mimic Octopus and the Indo-Pacific Shallows
Researcher Godehard Kopp at the University of Göttingen has studied the neural basis of octopus behavioral flexibility, and his work contributes to a growing body of research suggesting that the distributed nervous system of octopuses, with two thirds of their neurons in their arms rather than their central brain, may be particularly well suited to producing the kind of rapid, whole-body behavioral switching that mimicry requires.
Thaumoctopus mimicus lives in the shallow, sandy, estuarine environments of the Indo-Pacific, from the Red Sea through Southeast Asia to Australia. These environments are among the most biologically productive and most threatened in the ocean, subject to coastal development, sedimentation from deforestation, and coral reef degradation.
The mimic octopus is not currently listed as threatened, but its habitat specificity makes it vulnerable to the degradation of the shallow coastal environments it depends on. An octopus that has evolved the most sophisticated behavioral mimicry documented in any animal cannot mimic its way out of a habitat that no longer exists.
