Measuring just about 20 centimeters long, and covered in a mesmerizing pattern that delights the eye, the Blue-Ringed Octopus spends most of its time hiding close to shore. You might know that this lovely little octopus is actually deadly, as it is armed with a powerful neurotoxin strong enough to kill an average-sized adult human in a matter of minutes; learning how to tell when it is about to bite can prevent an accident.
A Rapid Warning
Two seconds isn’t much time at all in the human world, but to some cephalopods, it’s more than enough time to completely change their posture, color, and even their skin texture. If you think this is amazing, prepare to be stunned; the Blue-Ringed Octopus flashes its electric-blue warning display in under a third of a second.
A team of scientists working with the octopuses decided to film them at super-slow speeds in order to determine just how this rapid warning system works. In order to understand their findings, you’ll need a little bit of basic information about how the octopuses control their skin.
The colored structures in the octopuses’ skin are called chromatophores. These allow for rapid color changes, and are controlled by tiny muscles. Iridophores, which are firm, iridescent sheets of colored tissue, lie just beneath the chromatophores. A third type of tissue, called leucophores, add lumosity by reflecting light. In some octopuses, these structures can take a few minutes to change. This makes the Blue-Ringed Octopus’s ability to transform itself so rapidly even more amazing.
To make the bright blue color of the rings on its body stand out even more, the Blue-Ringed Octopus uses its chromatophores to darken the brown circles around the rings, and to lighten the paler areas between those rings. This not only makes for some incredible-looking underwater photos, it sends a clear message to predators that might otherwise mistake these deadly octopuses as suitable prey.
Marine biologists have discovered that the blue-green portion of the color spectrum is one almost all potential predators are able to see, and it’s one that travels well throughout the undersea light field. Birds, whales, fish, seals, and even other cephalopods are able to pick up on the warning message the octopuses flash; not only does this help those predators prevent illness or death, it helps save the Blue-Ringed Octopus from being eaten.
Unlike most other animals that use a system of iridophores to effect color changes, the Blue-Ringed Octopus does not use chemical signals in order to alter its skin coloration when needed. The fact that its color changes are controlled via muscle contraction is what allows the little animal to change its color so rapidly. This is the first time researchers have witnessed an animal using this type of activity to change its appearance.
While it is astonishing that these beautiful little octopuses are capable of controlling their bodies to such an extensive degree, the knowledge that these animals actually provide a distinct warning is definitely beneficial to divers. We already know that we need to keep our hands away from marine life; knowing what to watch for can help ensure we keep a respectful distance from these tiny, yet deadly creatures and enjoy watching them from afar.