For those preferring fresher evidence, in 1992 a killer whale had washed up dead on a beach of Prince William Sound, its stomach containing ID tags once attached to the flippers of fourteen Steller sea lions.
For Estes, who was still watching his otters vanishing down the line, these were intriguing and troubling developments. If the killer whales, and not the fishing boats, were the ultimate cause of the sea lions’ decline, that reopened the question why. He turned to his colleague Alan Springer from the University of Alaska at Fairbanks for a fresh perspective. Springer’s authority lay in the broadscale ecology of the Bering Sea; he was an expert on the ecosystem’s flux and flow, from plankton blooms to seabird crashes and back. Springer was just far enough removed from the entrenched combatants in the sea lion wars to free himself for more irreverent hypothesizing. What if, Springer offered, those blaming the fishing boats were only half wrong? What if the boats that had started this whole mess were whaling boats?
Decades before factory fishing boomed upon the Bering Sea, another great invasion had visited with the end of World War II, when the industrial whaling fleets set sail. The new battleships were swift, diesel-powered cruisers armed with cannons firing exploding harpoons. Whalers from Japan and Russia, rushing to rebuild battered postwar economies with this sea-bound bonanza of meat and oil, pushed into the demilitarized waters of the Pacific, across the Aleutians to the North American coasts. They came chasing the biggest and fastest of whales, the blue and fin, sei and sperm whales, in a massive blitzkrieg of the world’s biggest animals.
By the time the blitzkrieg went bust a mere twenty years later, half a million great whales had been mined from the North Pacific and southern Bering Sea. Taking into account just the troubled waters of the Aleutians and Gulf of Alaska, the harpooners had consumed three and a half billion pounds of whale. And that, to Springer’s and Estes’s growing suspicion, amounted to removing one towering mountain of killer whale sustenance. Maybe for want of whale meat, the killers had turned to smaller fare.
Weapon of Mass Destruction
In 2002, Estes took his and Springer’s nascent theory for a road test. To an auditorium packed with predator biologists and conservationists in Monterey, California, he delivered the conference’s plenary address, so innocently titled “Ecological Chain Reactions in Kelp Forests.”
A tall handsome figure at the podium, squint-eyed and trim-jawed and soft-spoken in the classic Clint Eastwood tradition, Estes called to mind the master’s flair for understated drama. “Do carnivores matter in this web of life?” began Estes, foreshadowing something other than a simple discourse on seaweed.
“Big carnivores occur in every ecosystem of the world, or at least they did at one time,” Estes continued. “The question of whether they matter depends on the resolution of top-down versus bottom-up forces. If bottom-up functions to the exclusion of top-down, then top-down doesn’t matter. But if top-down forcing is important, then the carnivores might matter a great deal. I’m talking about a ripple effect, rippling all the way to the base of the food web.”
The story thus began with a recap of Estes’s own historic discovery of the sea otter as keystone keeper of the kelp. Then on it went to the startling crash of the mid-’90s, the return of the urchin barrens, the utter bewilderment. “I initially just didn’t believe it. My mind-set was that these populations should be increasing,” he said.
Enter Tim Tinker and the killer whales, the otters’ port in the storm at Clam Lagoon, the astounding caloric calculations of Terrie Williams—all pointing to the mighty potential of the ocean’s apex predator.
“Why did all this happen? I’m less certain about what I’m going to tell you,” Estes told the crowd.
For lack of sea lions, Estes explained, the killer whales might be switching prey. Which of course then raised the $1.5 billion question: Why the lack of sea lions?
“That’s a tough one,” said Estes. “There’s a lot of disagreement. There’s emotion, money, and politics. There are entrenched theories.” But there was also, he revealed, the soon-to-be published conclusions of the National Academy of Sciences, which had taken a crowbar to those same entrenched theories. For all the respectable scenarios invoking starvation of the sea lions by fishing boats or climate change, it was at least as plausible that something had simply eaten them up.
So, continued Estes, here slowly unwrapping his bombshell, if killer whales had eaten all the sea otters, might not they have decimated the Steller sea lions as well? Considering their needs and capacities, as few as twenty-six killer whales could have done the job.
With note-takers in the audience now rechecking their pads —did he say, twenty-six? —Estes flashed an image on the big screen, bringing a collective gasp. It was a stark studio shot with black backdrop, the frame filled by a pair of enormous fangs. At a glance, they looked identical. One indeed belonged to a killer whale, confirmed Estes. The other had come from a Tyrannosaurus rex.
The killer whale came equipped for bigger prey than mere one-ton sea lions, said Estes. “Killer whales fed on all the great whales. Early whalers called them whale killers.”
Early whalers were, of course, whale killers too. Their postwar massacres had left the competition desperate, Estes suggested. For want of larger prey, killer whales had begun picking off the next convenient prospects down the line, from harbor seals to Steller sea lions to sea otters, which had apparently collapsed in suspicious sequence across western Alaska.
It was an ecological chain reaction that had spanned sixty years and six links in the food chain, from World War II to the twenty-first century, commercial whalers to kelp forests. “If you were to go out there today, you would not have a clue to what happened,” Estes told the carnivore conferees. “Without some notion of history you would have no inkling.”
“Carnivorous animals are important,” ended Estes. “We have to stop thinking of them as passengers on this earth and start thinking of them as drivers.”
Shots Across the Bow
Later that year, Estes, Springer, and seven collaborators submitted a formal account of their whaling hypothesis to the journal Science. And sometime after that, their star treatment came to a strange and inglorious end.
To the authors’ befuddlement, the Science paper came back twice —first with a few encouraging suggestions for revision, the second time with a fatal rejection, appended with a caustic dismissal from one of the reviewers: Everybody knows that Steller sea lions starved to death. That’s a fact.
Everybody, to Springer’s and Estes’s understanding, included neither themselves nor the National Academy of Sciences, which had just published a book effectively capsizing the conventional wisdom on the sea lions’ nutritional demise. Their panel’s chairman, Bob Paine, also took issue with Science’s premature dismissal of the whaling hypothesis. It appeared the old guard of the sea lion debate was still wielding considerable political power over the scientific community. So Paine then wielded his. As special contributor to the Proceedings of the National Academy of Sciences, a journal with prestige of its own, Paine himself forwarded Springer’s whaling paper for publication.
The lines had been drawn. And soon some of the troops grew skittish. Just before Paine submitted the paper to the Proceedings, one of its authors withdrew his name. Douglas DeMaster, director of the federal Alaskan Fisheries Science Center, begged off, citing unsettled scientific disagreements with his coauthors and concerns of conflicting interests. (DeMaster was a member of the International Whaling Commission.) By whatever reason, DeMaster’s untimely departure heralded the heat to come.
In October 2003 the Proceedings published Springer and company’s paper, “Sequential Megafaunal Collapse in the North Pacific Ocean: An Ongoing Legacy of Industrial Whaling?” Its authors might as well have stoned a hornet’s nest. A stinging barrage of e-mailed vitriol and in-your-face insults came shooting back: You’ve let the fishermen off the hook. People are going to be shooting killer whales over this. This is scientifical
ly irresponsible.
To Springer’s crew, it became loudly apparent that their well-meaning hypothesis of sequential megafaunal collapse had breached the bounds of cordial scientific discourse. Pet theories had apparently been trod upon. Egos had been bruised. “There are a lot of agendas out there in the research community and in people’s professional lives,” speculated Springer. “And you don’t want to have the rug jerked out from under you by some upstarts who aren’t killer whale people, suggesting Why didn’t we think of that?”
Not all the angst, though, was necessarily in vain. Anyone looking to excuse the trawler fleets for ecological damages (of which there were many) now had a conspicuous new scapegoat in the killer whale. Within three months, U.S. senator Ted Stevens, an ally of the Alaskan fishing interests, had proposed that the government begin looking into this new evidence “that rogue packs of killer whales” were to blame for the North Pacific’s endangered sea lion.
As for Alaskans taking up arms against killer whales, biologists who’d spent time among them insisted the threats were not hollow. “The community out there will use any excuse to harm these animals,” said Marilyn Dahlheim, a biologist with the National Marine Fisheries Service, who for years had been following and photographing Alaska’s killer whales. “I look at a lot of pictures of killer whales, and I see a lot of bullet wounds.”
If to no better end, Springer and company’s killer whale hypothesis had forced everybody concerned to take a fresh look at the animal they thought they already knew.
The Killer Whale
Orcinus orca is by far the largest and most lethal member of the dolphin family. They are a toothed whale growing to thirty feet long, readily identified by striking contrasts of white on black, and a sickle-shaped dorsal fin that on males may stand six feet tall. The head is massive and blunt, the tail a muscular fluke that can propel a six-ton body through the water at thirty miles per hour, arguably the fastest of all marine mammals.
The killer whale is the greatest predator on Earth, sea or land. It outweighs the largest land carnivore, the polar bear, by eight times, and occasionally eats them too. Killer whales are known to kill six-inch herring as well as sixty-foot blue whales. The killer whale attacks nearly everything that swims, including some that maybe shouldn’t; they are on record as having eaten dog, deer, and a moose. Great white sharks have been seen dead in the jaws of killer whales, and live ones apparently flee from the mere sound of them. Scientists opening the stomachs of killer whales have found the remains of fellow dolphins and porpoises, fish, octopuses, sea turtles, great whales of various forms, the occasional seabird, strands of seaweed, rocks (nine-pounds’ worth in the stomach of one killer whale), and recently of particular note, sea otters (five inside a killer whale found dead in Prince William Sound in 2003). The only dolphins yet to be documented as killer whale’s prey is the family of river dolphins. The only species of seal known to be safe from killer whales live in lakes.
The killer whale by necessity eats enormous quantities. Its metabolic furnace burns at twice the rate of terrestrial predators, ten times that of the largest sharks. On average, the killer whale must eat up to 5 percent of its body weight each day, which for the biggest bull whales comes to six hundred pounds. One excavated stomach contained the remains of fourteen seals and thirteen porpoises.
The killer whale’s teeth are all essentially the same, forty to fifty-two big, conical interlocking pegs, pointing slightly backward in the jaw. None are for chewing; all are for seizing and ripping. Their maw is capable of swallowing baby seals whole. What a killer whale can’t swallow, it rips to manageable chunks, often with a frenzied shake of the head.
For its predatory style, the killer whale is often compared to the wolf. It hunts in familial packs, combining guile, teamwork, tenacious resolve, and stamina to subdue quicker or more powerful prey.
Its hunting techniques are as varied as styles of art. Killer whales in Puget Sound herd salmon with their bodies and sonic voices, gathering the fish to be eaten one by one —the killer whale’s version of fishing in a barrel. Killers who chase herring in the Bering Sea have learned to gather the morsels by bashing a school of them with a slap of their tail, then picking the stunned ones like apples shaken from a tree.
Mammal- and bird-eating whales employ a range of tactics all their own. If they are after a penguin or seal huddled upon the ice, they may rocket from the depths to smash through the ice. In the frozen waters of Antarctica, packs of killers have been known to tip ice floes to spill stranded seals into waiting jaws.
A few killer whales in the Crozet Archipelago of the southern Indian Ocean, and half a world away on the South Pacific shores of Patagonia, have independently learned the same technique for snatching seal pups off the beach. They approach silently under cover of an incoming wave, barreling from the wall of water like a train out of a tunnel, then grabbing an unsuspecting seal pup or sea lion at water’s edge and thrashing the little animal like a rag doll.
Killer whales innovate and copy success. A killer whale held captive at Marineland in Ontario, Canada, learned to fish for gulls. The innovator, a young male, would spit out a fish from his daily rations. He would sink and wait out of sight for a scavenging bird to alight on the floating bait, then lunge. His little brother soon picked up the trick, followed by their mother. Eventually the entire killer whale community of Marineland had taken up the hobby of gull fishing.
Killer whales have also learned to train people. During the mid-1800s, a certain savvy pod of killer whales took to alerting the whalers of Twofold Bay, Australia, whenever there were humpback or right whales passing by. The killer whales would raise a ruckus, the whalers would spring to their boats, and as a team the two would go hunting together like hound and houndsman. The whaling men would reward their accomplices with first dibs on the tongues and lips of their catch.
Such predatory crafts and capabilities were common knowledge to any serious student of killer whale biology. Yet when it came to considering Springer and Estes’s interpretation of killer whales as whale killers, the heads started shaking no. The idea was too much to swallow. The logbook accounts of ancient mariners seemed too sketchy, too fantastic to make a case. Modern biologists who had spent hundreds of thousands of hours in the pilothouses and observation decks, without ever having witnessed an attack, could hardly believe they’d been missing the show.
Estes, on the other hand, was not at all surprised by that possibility. Estes, who had spent thirty years staring at one of the most accommodating subjects a wildlife biologist could hope for, had never seen a sea otter give birth. “Not only have I never seen them give birth, no one has ever seen them give birth,” he said. “I’ve actually gone through exercises: What would I expect to see, given the number of hours out there, and how few births occurred, how many would I expect to see? The expected number is about one. And we’ve seen zero.”
Ambush Alley
A funny thing happened during the killer whale debate. Observers began noticing killer whales killing other whales by the score.
In California’s Monterey Bay, through which gray whales pass on their annual migration from calving grounds in the Sea of Cortez to summer feeding grounds in the Bering Sea, professional whale-watchers looked on as killer whales started attacking gray whale mothers and calves with intensifying frequency. Between the years 2003 and 2004, the number of witnessed attacks went from two to two dozen. Monterey Bay had become known to insiders as Ambush Alley.
The same thing began happening as the grays rounded the Alaska Peninsula, funneling north through False Pass into the Bering Sea. There again the killer packs were roaming, taking as many as one in three of every gray whale calf that swam the gauntlet.
Ambush Alley and False Pass seemed to have rather suddenly become busier places. Whether a phenomenon of mounting attacks or the heightened vigilance of marine biologists, there was no denying that a certain faction of killer whales were making an increasingly conspicuous habit of killing gr
ay whales.
But it was still too hard for many to imagine killer whales attacking the greatest of the great whales —the fin, the blue, and the sperm whales, some of which were double the mass of the gray whale. Never mind that in the late 1970s, a research vessel off the tip of Baja had happened upon, and graphically filmed, a sixty-foot blue whale being eaten alive by a pack of thirty killer whales. That crew had witnessed in gory detail a five-hour assault that left the blue whale hideously mutilated, its tail shredded, its dorsal fin eaten, and a coffin-size crater of flesh and blubber excavated from its spine.
But if there was one whale in the ocean that might have seemed invulnerable to the ocean’s largest predator, it would be Physeter macrocephalus, the sperm whale —legendary slayer of giant squid, monster hero of Moby-Dick. The sperm whale was a formidable target reaching sixty feet long and forty-five tons, eight times the bulk of a killer whale. Before October 21, 1997, maritime history had left only nine records of attacks by killer whales on sperm whales, none of them lethal. On that day, some eighty miles southwest of California’s Morro Bay, whale biologists Robert Pitman and Susan Chivers and several researchers aboard the research vessel David Starr Jordan recorded the tenth attack.
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