Tuesday, March 08, 2016

Casper the friendly octopus

Octopuses are not normally considered "cute," but it's hard not to apply the appellation to the new species that reminds people of the cartoon character Casper the Friendly Ghost.  (That's better than referring to a problematic James Bond movie title.) The animal was plucked from a rocky shelf 4,290m down by the ROV Deep Discoverer off Hawaii. According to a NOAA scientist, it was the deepest that an octopus of this type (a member of the group called the incirrate octopuses) has been spotted, and among other oddities it has only one row of suckers on its tentacles instead of the standard two.  Even stranger, it lacks chromatophores and can't change color.  Welcome to science, little guy!

The newest octopus species (NOAA)

Octopus discoveries in the recent past are highlighted by the most wonderful species ever. Nothing found under the seas is stranger than a recently discovered Indo-Pacific octopus.  In the shallow waters of three straits off Sulawesi, Indonesia, lives an animal with an armspread of about two feet and an astonishing talent.  The Mimic Octopus, which has long, slender tentacles and is normally dark brown with white stripes and blotches, has powers of imitation unparalleled in the natural world.
The octopus can curl up its tentacles at its sides and darken itself to resemble a stingray, with one tentacle trailing at the back to make a tail.  It can turn tentacles into fake pectoral fins and look like the head and forebody of a jawfish rising from the seafloor.  It can arrange its entire shape and color to mimic a flounder and glide across the bottom.  It can resemble a starfish, a jellyfish, a sand anemone, a sea snake, a snake eel, a lionfish, or a baby cuttlefish.
Where does this little octopus learn such complex behavior, and what is this repertoire used for?  The octopus can imitate both prey species and predators, so it may use this ability as a defensive mechanism or a way to sneak up on prey, as the need arises.  However this behavior arose, and however it is passed on, it is a most impressive example of skill and adaptability among these “lower” animals.
Dr. Mark Norman of James Cook University in Queensland told me in email that he and his colleagues have nabbed no fewer than 150 new species of octopus in the last ten years.  Incidentally, Norman explained why there was a long delay in formally describing the the Mimic Octopus: “Everybody likes them too much to knock one off for formal description.”  He wrote the description of another long-armed species nicknamed "Wonderpus,” an Indonesian native which can mimic sea snakes.  (The Wonderpus and Mimic Octopus are occasionally confused in media reports, but they are two separate types.)  Among other descriptions he's written is that a species with very thin limbs three feet long, known to Norman as “Spaghettiopus.”
Gotta love those octopuses.  We've only started figuring them out. 

Further reading:
Colin, Patrick.  1999.  “Palau at Depth,” Ocean Realm, Summer, p.77.
Quammen, David.  2000.  The Boilerplate Rhino.  New York: Scribner.
Steene, Roger.  1998.  Coral Seas.  Buffalo, NY: Firefly Books.
Ross, John.  1999.  “Masters of Mimicry,” Smithsonian, March, p.112.
Turner, Pamela.  2003.  “Uncommon Octopus,” Wildlife Conservation, January, p.20.

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