Other Minds: The Octopus and the Evolution of Intelligent Life. Peter Godfrey-Smith

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СКАЧАТЬ with other animals. Quite a lot of the early work done in the Naples Zoological Station treated octopuses badly. Not only were electric shocks used, but many experiments included the removal of parts of the octopus’s brain, or the cutting of important nerves, just to see what the octopus would do when it woke up. Until recently, octopuses could also be operated on without anesthetic. As invertebrates, they were not covered by animal cruelty rules. Many of these early experiments make for distressing reading for someone who regards octopuses as sentient beings. Over the last decade, however, octopuses have often been listed as a kind of “honorary vertebrate” in rules governing their treatment in experiments, especially in the European Union. This is a step forward.

      Another octopus behavior that has made its way from anecdote to experimental investigation is play – interacting with objects just for the sake of it. An innovator in cephalopod research, Jennifer Mather, along with Roland Anderson of the Seattle Aquarium, did the first studies of this behavior, and it’s now been investigated in detail. Some individual octopuses – and only some – will spend time blowing pill bottles around their tank with their jet, “bouncing” the bottle back and forth on the stream of water coming from the tank’s intake valve. In general, the initial interest an octopus takes in any new object is gustatory – can I eat it? But once an object is found to be inedible, that does not always mean it’s uninteresting. Recent work in the lab by Michael Kuba has confirmed that octopuses can quickly tell that some items are not food, and are often still quite interested in exploring and manipulating them.

      ~ Visiting Octopolis

      In the first chapter I described Matthew Lawrence’s discovery of an octopus site on the east coast of Australia. Matt explored the bay by dropping an anchor off his small boat, swimming down to pick it up, and letting the drift of the boat guide his wandering over the sea floor. (I should add that diving alone is a bad idea. Matt takes down a second air supply that is completely independent of the first, in case things go wrong. Even then, it’s not recommended.) In 2009 he came across a shell bed with about a dozen octopuses living on it. They seemed unconcerned by his presence, roaming and wrestling with each other as he watched.

      Matt marked the GPS coordinates of the spot and began visiting regularly. He’d watch and interact with the octopuses. They didn’t seem to mind his presence at all, and some were curious enough to play with him and explore his equipment. His camera and air hoses soon had octopuses roaming over them. Others were too busy dealing with each other. Sometimes he saw what looked like a kind of “bullying” behavior. An octopus would be sitting quietly in its den, and a larger one would come over, jump on top of the den, and wrestle furiously with the one below. After a great multicolored convulsion, the octopus below would come flying out like a rocket, its body pale, and land a few meters away, just off the shell bed. The aggressor octopus would wander back to its den.

      As time passed, Matt became more and more accustomed to dealing with these animals, and to this day it seems to me that the octopuses treat Matt differently from anyone else. Once at a site close to this one, an octopus grabbed his hand and walked off with him in tow. Matt followed, as if he were being led across the sea floor by a very small eight-legged child. The tour went on for ten minutes, and ended at the octopus’s den.

      Though he’s not a biologist, Matt had a sense that his site might be unusual. He posted some photos on a website that functions as an information center for cephalopod-inclined hobbyists and scientists. There they were seen by the biologist Christine Huffard, who asked me: Did I know this place? I was startled when I read about what he’d found, and Matt’s site is only a few hours from Sydney. I got in touch when I was next in town, and drove down to meet him.

      Matt, I found, is a scuba fanatic. He keeps his own air compressor in a garage, where he concocts personalized mixes of enriched air to fill his tanks. Soon we were chugging out on his small boat to a spot in the middle of his bay, where he set the anchor and we swam down the line, observed by just a few small fish.

      The site we now call Octopolis is about fifty feet down. It’s almost invisible until you get quite close, and the sea floor around it is nondescript. Scallops live scattered in little clumps, or on their own, and various kinds of seaweed waft about on the sand. My first trip to the site, in cold winter water, was quiet. We found just four octopuses, who were not doing much. But I could tell it was an unusual place. There was a bed of scallop shells, as Matt had said, a couple of yards in diameter. It seemed to contain shells of many ages. An encrusted rock-like object, a foot high or so, sat in the middle, with the largest octopus on the site using it as a den. I took measurements and photos, and began coming back whenever I could. Soon I was seeing the high concentrations of octopuses and complex behaviors that Matt had encountered on his first dives there.

      If we had air enough and time, I don’t know how long we’d stay down there. When the site is active, it’s enthralling. The octopuses eye each other from their dens among the shells. They periodically haul themselves out and move over the shell bed or away onto the sand. Some will pass by others without incident, but an octopus might also send out an arm to poke or probe at another. An arm, or two, might come back in response, and this leads sometimes to a settling-down, with each octopus going on its way, but in other cases it prompts a wrestling match.

      The first photo on the next page was taken just off the edge of the site, and it’s to give you a sense of how these animals look. The species is Octopus tetricus, a medium-size octopus found just in Australia and New Zealand. This is a fairly large individual; from the sea floor to the high spot at the end of its back would be a bit under two feet. It is rushing toward another octopus, off to the right.

      The next scene is on the shell bed itself. The octopus on the left is leaping toward the one on the right, who is stretched out and starting to flee.

      Frame from video taken by unmanned cameras (collaboration by Peter Godfrey-Smith, David Scheel, Matt Lawrence and Stefan Linquist).

      And this is a more serious fight, on the sand just off the edge of the site:

      In order to study changes in the shell bed, I once brought out some stakes and hammered them into the sea floor to mark the site’s approximate boundaries. The stakes, about seven inches long, were made of plastic, so I taped a heavy metal bolt to each one to give it more weight. I drove the stakes in so that only an inch or so of each one sat above the sand, and placed them at the four compass points. They’re very inconspicuous, hard to see unless you know exactly where to look. Some months later I went out to the site again, and found that one of the stakes had been hauled out and added to the pile of debris around one of the octopus dens, some distance away. The stake, I think, would have quickly been found inedible, and it was probably not especially useful as a barricade. But as with tape measures, cameras, and many other things we bring down to the site, the stake’s novelty seemed to make it interesting to an octopus.

      Other octopus manipulations of foreign objects are done for more practical reasons. In 2009, a group of researchers in Indonesia were surprised to see octopuses in the wild carrying around pairs of half coconut shells to use as portable shelters. The shells, neatly halved, must have been cut by humans and discarded. The octopuses put them to good use. One half-shell would be nested inside another, and the octopus would carry the pair beneath its body as it “stilt-walked” across the sea bottom. The octopus would then assemble the halves into a sphere with itself inside. A wide range of animals use found objects for shelters (hermit crabs are an example), and some use tools for collecting food (including chimps and some crows). But to assemble and disassemble a “compound” object like this, and put it to use, is very rare. It’s СКАЧАТЬ