The Dynamic Shape-Shifter
The mimic octopus, Thaumoctopus mimicus, was formally discovered in 1998 off the coast of Sulawesi, Indonesia. It lives in shallow, murky river mouths and estuaries, preferring sandy or silty seabeds at depths of less than 15 meters. Unlike most octopus species which favor the shelter of reefs, T. mimicus thrives in open areas, a habitat choice made possible by its sophisticated defense mechanisms. This octopus is relatively small, with a total length of about 60 cm, and its arms have a diameter similar to a pencil. Its natural coloration is a pale brown or beige, but it frequently displays bold brown and white stripes to ward off threats.
This species is the first known to impersonate multiple other animals, a behavior called dynamic mimicry. While other cephalopods use their color-changing skin cells, called chromatophores, for camouflage against a static background, the mimic octopus actively changes its shape, movement, and coloration to imitate other specific creatures. This is a behavior.
A Repertoire of Disguises
The mimic octopus has an extensive catalog of impersonations, with at least 15 to 16 different species documented. Its choice of disguise is not random; evidence suggests it selects a mimic that poses a direct threat to its potential predator. For example, when harassed by territorial damselfish, a mimic octopus was observed impersonating a banded sea snake, which is a known predator of damselfish.
Some of its most common impersonations include:
- Flatfish: It pulls all eight arms together into a leaf-like shape, flattens its body, and propels itself over the seabed with jet propulsion, perfectly matching the undulating swimming motion of a poisonous sole.
- Lionfish: The octopus spreads its arms radially around its body to look like the venomous spines of a lionfish. It then hovers above the seafloor to complete the illusion.
- Sea Snake: It hides six of its arms in a burrow or beneath its body, extending the remaining two in opposite directions. It then changes its color to match the yellow and black bands of a venomous sea snake and waves the two visible arms in a serpentine motion.
Beyond these, T. mimicus has been seen mimicking jellyfish, sea anemones, mantis shrimp, and stingrays. This ability to strategically deploy different, complex disguises shows a level of intelligence and environmental awareness.