The Mysterious Blanket Octopus

Who knew that there was such a thing as a blanket octopus with a self-defense mechanism unlike any other? Ellen Prager did and she wrote about the unusual blanket octopus and many other highly unusual facts about natural marine life in her new book, Sex, Drugs and Sea Slime. Along with the unbelievable blanket octopus, Prager expounds on fascinating natural history of jawfish who incubate their eggs in their mouth, octopi who self-amputate their sexy arms and parrotfish that wrap themselves in a blanket of snot.

All these natural facts of marine life are anecdotes that we reef keepers take for granted on a regular basis but they really are very strange if you step back to think about it. Although we haven’t read it yet, something tells us that Prager’s book about these marine life facts will have a refreshing unjaded point of view that we would expect from a non-aquarist. Posted below is a  video of the blanket octopus unfurling its unbelievably long flap of skin in self defense and if you are interested, there is an excerpt of Prager’s book available to preview online.

These species exhibit an extreme degree of sexual dimorphism. Females may reach 2 metres (6.6 ft) in length, whereas the tiny males are at most a few centimeters long. The males have a specially modified third right arm which stores sperm, known as a hectocotylus. During mating, this arm detaches itself and crawls into the mantle of the female to fertilize her eggs. The male dies shortly after mating. The females carry over 100,000 tiny eggs attached to a sausage-shaped calcareous secretion held at the base of the dorsal arms and carried by the female until hatching.

Blanket octopuses are immune to the poisonous Portuguese man o' war, whose tentacles the male and immature females rip off and use for defensive purposes. Like many other octopuses, the blanket octopus uses ink to intimidate potential predators. Also, when threatened, the female unfurls her large net-like membranes that spread out and billow in the water, greatly increasing her apparent size.

The Blanket Octopus The Blanket Octopus’ name is derived from the long, clear webs extending from the dorsal arms of the a mature female – yeah, it looks sort of like a see-through blanket (let’s just hope they never come out with a Snuggie Octopus)