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4 february 2011

Octopus: The ocean's intelligent invertebrate is both an intelligent book and a fascinating window onto contemporary scientific practices. Jennifer Mather, Roland Anderson, and James Wood are three of the world's most knowledgeable octopus scientists. There's a popular notion that every aspect of the natural world must be known inside and out by massed batteries of scientists who continually monitor the Universe and winkle out its secrets. In reality, octopus scientists (let's say) must scratch for those little bits of knowledge that institutions like universities and aquariums may find a little money, here and there, to subsidize.

To learn about the octopus – neither the sea's most charismatic nor its most commercial creature – scientists either keep some octopuses in tanks and watch what they do, or swim around in the ocean and watch what free octopuses do. It's possible to design octopus experiments, and Mather et al. describe some elegant ones. But rigorous analysis of octopus behavior is kind of like wrestling an octopus.

Despite the shape- (and color-) shifting nature of their subjects, octopus researchers have learned a great deal in the course of their invertebrate ethology. Octopus is structured around the life cycle of the great cephalopods. Hatching from eggs laid at the sea bottom, most (though not all) octopus young float upwards and hang out in the plankton for a while, getting a little fatter.

And when they've grown large enough, they descend. This must be a terrifying moment for an intelligent creature – though the authors don't really speculate on the nature of octopus terror. Octopuses are bottom-dwellers, so they must plummet from the surface and find a home in the same action, much as if you were moving to a new city and had to pick out a house on your final descent toward the airport. Presumably this doesn't often work out. But octopuses are hatched by the billions and billions, so it doesn't need to work out often.

Once there, they are one of the more efficient monsters of the deep. They can change shape and color (as I've noted), squirt ink, hang onto things with amazing strength and dexterity, drill holes in clamshells, crack crab, and fight pitched battles with moray eels. They will eat any kind of animal, including one another. Scientists are not sure how the eight arms that give them their name are coordinated by octopuses. How octopuses control single arms "was last studied by C.H. Fraser Rowell in the 1960s," say the authors (87), and "no study of neural control and coordination of multiarm movement has been done since the work by W.J. ten Cate in 1928" (85). I suppose these lacunae in science are due to two factors: it's not real easy to give an octopus a brain scan, and even if you could, nobody's going to fund such research: it won't put an octopus more or less on the sushi bars of the world.

Octopuses are not particularly endangered. They are opportunists, slithering into all kinds of ecological niches. (Smaller octopuses love to live in discarded beer bottles: recycling may actually reduce their habitat.) Although they're smart and learn quickly, often with highly individual styles, octopuses are short-lived. As soon as they mate, they immediately grow old and die. (Males at once; females after hatching their eggs.) In this respect, the octopus is the opposite of the tortoise, which seems not to grow old at all.

Octopus ends with instructions on how to keep your own octopus as a pet, but since (like eels) they love to climb out of their tanks, I think I'll stick with cats. I do not think I could handle an octopus tapping on the bedroom door and climbing onto my covers at night.

Mather, Jennifer A., Roland C. Anderson, and James B. Wood. Octopus: The ocean's intelligent invertebrate. Portland, OR: Timber Press, 2010.