As reclusive murk dwellers go, 20-foot-long bluntnose six-gill sharks are impressive critters—impressive enough to make local TV go gaga over the "discovery" of them in Puget Sound, even though you could see them for years in the Seattle Aquarium. And the orca is a magnificent top predator, a ravening hunter with heartwarming family values and a tragic canary in the Sound's toxic coal mine. But six-gills and orcas are found in all the world's seas. The most distinctive giant of these waters, our defining monster, is a shy mollusk the taxonomists call Enteroctopus dofleini—the giant Pacific octopus.
It's been 14 years since I first wrangled an invitation from Roland Anderson, the aquarium's invertebrate biologist, to meet the then-occupant of the octopus tank, a 40-pounder named Steve. (Octopuses are the only aquarium inmates other than adorable seals and otters that the keepers bother to name; this says something—perhaps about the sympathies of aquarists, but more likely about the charisma of octopuses.) Steve took a shrimp from my hand and stretched his tentacled arm up my own, affixing and releasing a hundred suction cups and tasting with the thousands of chemoreceptors in each cup. When he got to my neck, he decided I had no more shrimps to offer and retracted like a snapped rubber band, jetting me with his siphon and turning red—apparently the color of chagrin in octopuses as well as humans. Glowered, in a word. You have not encountered the living world's wonders until you have been glowered at by a mollusk.
As dofleini go, Steve was just a little squirt. Whether you believe the 45-year-old account of a 33-foot octopus supposedly caught near Victoria or the better-verified reports of 20- and 22-footers, these local giants are far and away the world's biggest octopods and, giant squid aside, the largest invertebrates on earth.
But brains before brawn: It's the mental and neuronal capabilities of octopuses—and their squid and cuttlefish cousins—that are truly astonishing. That they have complex, centralized brains at all, let alone bigger brains than most vertebrates, sets them apart from other invertebrates.
Many of those invertebrates—bees and ants, sea stars, and earthworms—are more closely related to us than the octopus. Its primitive ancestors, according to the best nuclear divergence reckoning, split from ours some 1.2 billion years ago. Evolution abounds in marvels undreamt of in your creationist philosophies; that our line and the cephalopods' should have converged in so many ways is surely one of the most marvelous.
Researchers have been shoving electrodes into cephalopods and plunking them in mazes for decades. The research has located separate short-term and long-term memory centers in the creatures' brains and recorded distinctly vertebratelike slow brain waves, unlike the spiky static other invertebrates emit. Octopuses can recognize individual humans, remember mental maps, learn mazes and arbitrary cues, and apply what they've learned in reversed circumstances.
Lately, research has progressed from cephalopods' cognitive to—dare we say it?—their emotional lives. The aquarium's Anderson and Jennifer Mather of Lethbridge University are in the vanguard of this inquiry, which some of their more cautious colleagues see as rashly speculative. They've described what they call distinct "personalities" in octopuses. They've recorded "play behavior"— important to learning and reported widely in mammals, occasionally in birds, but never before in invertebrates—in octopuses. When eight giant Pacific octopuses were given floating pill bottles, two used their jets to blow them repeatedly into their tanks' intake jets. One made the bottle circle the tank and the other made it rebound as though bouncing a ball.
Since I started following this research, I haven't been able to look at Elliott Bay's dark waters without wondering what eight-legged jocks, geniuses, and sensitive souls may writhe and brood below. And my list of sushi choices has shrunk by one; hold the tako, please. But at least we don't need to worry about the octopuses as we do about Puget Sound's orcas, salmon, herring, and bottom fish. The smaller Octopus rubescens seems to be thriving with help from boaters who toss beer bottles overboard; these make perfect dens. This year's octopus census, which Anderson leads, turned up many more giant Pacific octopuses than last year's, though that may just reflect good weather and more divers surveying. No octopus anywhere is considered endangered, but that may just reflect ignorance; perhaps half the existing species haven't even been identified.
And Anderson has lately spotted "preliminary" danger signs. The aquarium's giant octopuses, which used to reach nearly 100 pounds, were topping off at 76, then 56, 55, and 46 pounds. He wondered if the crabs they ate, caught off the aquarium's pier, might play a part. These showed whopping levels of various industrial metals—copper, zinc, manganese, and tin. So did the octopuses' digestive organs. Anderson stopped feeding them waterfront crabs, and the giants became giants once again.
These crabs, which people likewise eat, are also loaded with PCBs, as was the one octopus tested for them. It hadn't seemed that octopuses—which, like salmon, live four years or less—had time to accumulate toxins. Guess again. We may be getting to know another local giant just as we are destroying it.
Eric Scigliano's environment column appears every other week.