For the first billion years of life on Earth, all of our ancestors were single celled. One day, we aren’t sure why, a hungry organism ate a delicious bystander, and became the first predator. Predation inspired evolution to become very creative. Some organisms became mobile by developing cilia or tails. Others shape shifted into multi-celled life forms. Critters developed scales, spikes, shells, fangs, and many other clever defenses. Thus, one group survived by dining on the unlucky, and the bigger group survived by evolving every imaginable trick for cancelling lunch dates with predators.
When predators became too powerful, they would wipe out their food supply, blush with embarrassment, and starve. Prey that managed to survive evolved stronger defensive capabilities. But if they got too good at this, their population would explode, deplete the available nutrients, and the vast mob would perish in an undignified manner.
Thus, evolution is an elegant balancing act. If the prey gets one percent faster, the predator gets one percent faster, not two. This balancing act is the subject of William Stolzenburg’s book, Where the Wild Things Were. More specifically, the book focuses on how humankind uses its brilliant technological innovations to bypass the limits of our current state of evolution, upset healthy balancing acts, and devastate ecosystems, often unintentionally.
In the early 1970s, zoologist James Estes travelled to the Aleutian Islands of Alaska to do research on sea otters. Sea otters can grow up to four feet long (1.2 m), and they have incredibly soft fur. Stylish women with too much money loved wearing fur coats, and for 150 years, from Alaska to Baja, otter hunting was a serious business, and very profitable. Somewhere between 500,000 and 900,000 otters lost their hides to the fashionable dames of high society.
The island of Amchitka had a healthy population of otters, and this is where Estes began his study, scuba diving in frigid water. Beneath the waves were thriving jungles of kelp, a popular hangout for a number of aquatic herbivores. Kelp can grow up to 200 feet tall (61 m). Urchins enjoy dining on kelp, and sea otters enjoy dining on urchins. What Estes observed was a healthy balance between the kelp, urchins, and otters.
Later, he spent some time on the island of Shemya, where the great extermination had wiped out the otters. Only a few had since recolonized there. The ecosystem here was stunningly different from Amchitka. In the absence of otters, the urchins exploded in numbers, and many were huge in size. The sea floor was wall-to-wall urchins, and there was no kelp at all.
So, when the keystone predators (otters) live in peace, the ecosystem is healthy and balanced. When they are eliminated, the ecosystem becomes a train wreck — a chain reaction known as a trophic cascade. Predators are essential.
A similar scenario occurred when Zion National Park was established in Utah. To make the park safe for tourists, the cougars (mountain lions) were exterminated. In their absence, the population of mule deer exploded, and the land was stripped of vegetation. The forests were dying, because young seedlings were devoured by deer. Meanwhile, over the hill in North Creek Canyon, the cougars had been left alone, and the land was remarkably alive and healthy.
The Kaibab Plateau in Arizona became a game preserve in 1906. Deer hunters were kept out, and 6,000 large carnivores were deleted. The deer population skyrocketed from 4,000 to 100,000, and the vegetation was promptly vacuumed up. In the winters of 1924 and 1925, 80,000 deer starved to death. Ecosystems pay an enormous price for the stunning ecological ignorance of literate, educated people, who spend years in miserable classrooms carefully absorbing spooky illusions.
Wolves and grizzlies had been absent in the Tetons for quite a while. Then, a few began drifting in from Yellowstone. At first, the moose and elk had no fear of them. Wolves calmly strolled into the herd and snatched their young. Before long, they learned that fearing predators was beneficial. Something similar to this innocent fearlessness likely existed in every ecosystem when humans first arrived with their state-of-the-art killing technology.
In the 1950s, Paul Martin connected some archaeological dots. The megafauna of the world, that had survived almost two million years of ice ages, suddenly blinked out whenever armed humans arrived in a new region.* This realization gave birth to his Pleistocene Overkill hypothesis, “that man, and man alone, was responsible for the unique wave of Late Pleistocene extinction.” Despite many loud objections, it has generally been accepted, but it fails to explain the large numbers of mammoths and rhinos found in Siberia and Alaska. It also causes those who worship at the crumbling Temple of Human Omnipotence to become moody and irritable.
Whatever your opinion on this controversy, it’s easy to argue that during the long era of warm weather (since 9600 B.C.), the pristine state of America was the Pleistocene, not 1492. In 2005, a group of biologists published a paper on rewilding in the journal Nature. It recommended the reintroduction of missing species like cheetahs, camels, lions, and elephants. The mainstream crowd soiled their britches and howled hysterically.
It was, like, totally groovy to reintroduce pretty butterflies, but the huge backlash boiled down to “no lions in my backyard!” This was the lively kickoff for what will be a long and bumpy process of attitude evolution — or a fierce backlash from those who have yet to free themselves from the tiny cage of anthropocentric hallucinations.
I wonder if the systematic extermination of millions of predators over the years is associated in any way with the current explosion in the human population. When climate change forced our ancestors onto the savannah, evolution had not prepared us for living amidst fast, powerful, heavyweight predators. We developed a highly unusual dependence on technology in order to survive, thereby knocking over the evolutionary balancing act. “They would eventually wield the power to level mountains, to dam the biggest rivers, to coat entire continents in concrete and crops, to alter the climate as it had once altered them.” The chapter on how we morphed into apex predators is fascinating.
Today, we almost never encounter man-eating predators running lose. We no longer have to pay careful attention to reality, ready to react at any moment, fully present and alive. The world has become safe for pudgy cell phone zombies — an empty, dull, and lonely place. This is seen as normal. I disagree.
* Megafauna survived in Africa because they evolved together with hominids, but there’s more to the story. Lars Werdelin, a specialist in African carnivores, has learned that there used to be far more large carnivores. Between 2 and 1.5 million years ago, many large carnivores went extinct. This is about the time that tool-using, meat-eating Homo erectus appeared. (Werdelin, Lars, “King of Beasts,” Scientific American, November 2013, pp. 34-39.)
Stolzenburg, William, Where the Wild Things Were, Bloomsbury, New York, 2008.