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THE NATURALIST
by Dave Evans

Tidepool Intellect
July 31, 2002

On those calm and sunny days when we have a good minus low tide, the supreme find for the tidepooling group is first just a glimpse of suckered tentacles under a rock. OCTOPUS! The cry goes out and the whole group of tidepoolers converges on the location.

Last weekend's sighting was not our usual encounter with what is often a secretive creature, contorting its flaccid body to fit in the smallest crevices under the rocks. Yes, the animal did duck under a rock, but it soon swam out from under the opposite side, and made its way through a network of channels to open water. Measuring about a yard from tentacle tip to tentacle tip, it kept its large staring eyes on the tidepoolers the entire time. I'm used to taking groups down to the shore of Monashka Bay, and observing a huge variety of organisms we encounter. I'm not really accustomed to those organisms observing us. But now we had a pair of unblinking image-forming color-sensing and baleful eyes focused on us. The animal was WATCHING us tidepoolers! And with the intelligence it has, I couldn't help wondering just how it was interpreting what it saw?

Our Kodiak variety is the Pacific octopus, which feeds on smaller marine animals by grasping them with the sense organ-rich suckers on its tentacles and biting with its beak or drilling through with a toothed tongue-like structure, the radula. Venom immobilizes the prey. Sometimes an octopus will establish a den under a rock, recognizable by remains of victims: piles of shells, crab carapaces, and sea urchin skeletons.

Putting ourselves in the sensory world of another species and then trying to speculate on how the animal is processing the information it receives is one of the greatest challenges facing students of animal behavior. It may be easier when we try it with vertebrates like fish, birds, or mammals that have at least some more apparent similarities to us in nervous system or sensory apparatus. Trying it with an invertebrate as remote from us as an octopus is like speculating on perceptual worlds of beings from a parallel universe.

They are different from us. They have no skeleton. They have three hearts--two to pick up oxygenated blood from the gills and one to send it to the rest of the body. Their blood is blue, and the copper-based pigment octopuses use as an oxygen carrier is not particularly efficient. It restricts some important activities to a slow and deliberate pace. Even mating is a sort of distracted process, with the female detachedly grazing on food while the male puts forth his best courtship efforts. Come to think of it, that last does remind me of my high school social life in some ways.

These are intelligent invertebrates, perhaps the most intelligent. They have memory centers in a large brain, and they can recognize individual humans, learn to run mazes (well, not run, exactly, more slither and jet), they can open screw-top bottles, and learn by observing other octopuses. They'll show begging behavior in aquariums when feeding time comes, and have even been seen indulging in what may be play. Play in this case consisted of squirting a jet of water at a floating Tylenol bottle so that it moved back and forth between the octopus and the flow of water from an aquarium filter. Of course that's a game that never gets old. More in the interests of scientific consistency than pharmaceutical product endorsement, the scientists provided a series of octopuses with Tylenol bottles, and found that play varied from the bouncing ball variety just described to gently squirting water jets to make the floating bottle circle the aquarium.

I feel a bit awkward about handling or otherwise distressing any of our tidepool organisms, but particularly so about the octopus. And I'm guessing it does feel distress. Of all the invertebrates along the Monashka Bay shore, it alone has the nervous system, sensory equipment, and complexity of behavior that would allow an animal behaviorist to make that statement.

David A. Evans, Naturalist, Fort Abercrombie State Historical Park


http://www.kadiak.org/naturalist/tidepool_intellect.html Updated 2002 August 14

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