Octophilia

 kw: book reviews, nonfiction, science, oceanography, natural history, octopuses

For most of my life, the colloquial plural of "octopus" was "octopi". Later, I read that either "octopods" or "octopoda" would be a better choice, but these never stuck. The accepted plural now is "octopuses". We've welcomed the word "octopus" fully into the English language, rather than as an Anglicized Latin or Greek term.

David Scheel became enamored of octopuses while engaged in his first oceanographic survey project as a P.I. (Principal Investigator). He had a grant application accepted, despite, as he admits, a rather severe shortage of experience. It doesn't seem to have held him back. He primarily lives in Alaska, but has studied octopuses all over the world. His new book Many Things Under a Rock: The Mysteries of Octopuses brings his experiences to us. Chapters are introduced by line drawings by Laurel "Yoyo" Scheel, whom I presume to be his daughter. I just wish he'd also included a bunch of photos in the book, even if it raised its price. 

The book's title is a translation of the Eyak word for octopus, tse-le:x-guh, and aptly describes how an octopus appears when you look under the rock into its den. I don't know how that word is pronounced, but I suspect ":x" is a click combination. The Eyak people are a group of those often called Aleuts, living on the Alaskan islands. They catch octopuses to eat, as do many coastal people the world over.

It's amazing to me that these highly intelligent creatures—on a par with the brightest of birds and possibly with porpoises—seldom live more than a year or two. One species, Graneledone boreopacifica (there is no common name; they live a mile or more deep) is known to brood eggs as long as 4.5 years, but their full life span is unknown.

Dr. Scheel's first study subject was the Giant Pacific Octopus. The largest verified specimen weighed 437 pounds. Even a more-common one weighing 50 to 100 pounds can grab someone by the leg and hold them underwater; one chapter records someone's experience of this. That fellow managed to get away before drowning, but lost some skin in the process. Most species weigh a few pounds or less. I encountered one in a tide pool, poked it with a stick, and found my hand grasped when a tentacle unrolled along the stick and "shook hands" momentarily. I think it was more curious than irked (fortunately!).

The four sections of the book, grouping together 22 chapters, are titled "Where are they?", "Want", "Reach", and "Revelation". Every section is fascinating; here I'll just touch on "Reach", which is about octopus senses. 

The last chapter in this section is the best: 16 Dreaming Octopuses. It's pretty well established that they do dream, and this probably extends to all cephalopods; other cephalopods include squids and cuttlefish. The octopus in this image is dreaming, and the shifting colors and textures (note the papillae on the head) seem to correspond to our experience of REM sleep. The animal's eyes are not closed, but experiments have shown that they don't see much during octopus sleep; just enough to detect an oncoming predator.

Curiously, the eyes of octopuses have only one light sensing pigment, which means they are color blind…or are they? Their skin is light sensitive, and the chromatophores (color-displaying cells) seem to act like filters, allowing color sensing by the skin. The eyes are also sensitive to something ours are not: polarized light (unless we are wearing polarizing shades). Try to wrap your mind around this: seeing with your eyes in shades of gray, such as by the light of a quarter moon (when your color vision has shut off), yet having colors supplied by your skin, and an overlay of polarization (somehow). Would humans wear clothing if an important organ of vision was their skin, with its 360° view?

Chapter 15 Constant Octopuses delves into the experience of constancy. When we are moving smoothly, it appears that the scenery is in motion and we are stationary. Yet if we move a hand, either with our counter to the apparent motion of the scenery, it remains "attached" to us in our sense. Octopuses also experience a constancy of self. The author expands the discussion to the matter of how any animal distinguishes self from not-self. Is this the core of consciousness? It seems likely! This implies that consciousness and self-awareness are not on-off traits, but occur as a spectrum.

Finally, I must mention the spectrum of sociability. Octopuses are generally considered asocial and sometimes antisocial. Yet they do need to get together to mate. More recently, octopuses have been found in aggregations in which they display quite a range of social behaviors. The last three chapters explore this.

At one extreme, if two octopuses differ in size, the larger one will frequently eat the smaller one, or at least try, whether they are the same or different species. If a large female who is a bit hungry is approached to mate by a smaller male (in some species the males are much smaller), she may try to eat him. Accidental meetings between two octopuses of similar size, particularly males, can engender a confrontation, as seen here. The dark coloration is the "I'll stand my ground!" signal, although the one on the left is likely to soon flee.

When one octopus decides to kill another, it uses something like a headlock, wrapping an arm around the head, sometimes using two arms. It tries to close off the mantle and siphon, suffocating the opponent.

In some settings, however, octopuses can be cooperative, as seen in this "nursery" full of females, nearly all wrapped around egg clusters in a defensive posture. The yellowish sea anemones are not typically eaten by octopuses because of the stinging cells on their own tentacles. (This image was very dim online; I've boosted the contrast quite a lot. I seldom perform more than cursory digital darkroom work on downloaded pictures.)

Many more subjects are covered, including octopuses as prey; as predators on crabs, clams, small fishes and each other; and tool use, including throwing things at each other when in social aggregations. There is so much to cover, and the author has done an admirable job of condensing a huge subject into this readable and fascinating book.