EVERY KID IN THE U.S. knows and cares about dinosaurs, but few have even heard of the Shasta ground sloth, let alone its contemporaries: American mastodons, western camels, Mexican horses, and American cheetahs and lions. Roughly thirteen thousand years ago, six dozen North American species over a hundred pounds went extinct. Human hunters probably played a part in their demise.
Three years ago my colleagues and I proposed restoring megafauna to North America using ecological history as a guide. Our idea: re-create the missing ecological functions and evolutionary potential of lost megafauna by using closely related species as analogues. It turns out the horses, camels, and cheetahs in Africa and Asia today are closely related to vanished North American counterparts. In fact, today’s “African lion” is the same species that once roamed North America. The social and ecological challenges of bringing megafauna back to North America are monumental, but so are the potential benefits.
Large animals maintain biodiversity through their interactions with other species. Elephants knock down trees and create new habitat. Lions regulate prey populations by eating them and affect their behavior by creating landscapes of fear. Similarly, wolves alter the vegetation by changing where elk go to forage, and these changes in vegetation patterns influence migratory birds. Wolves may even dictate the ability of other animals to survive by providing carcasses to scavenge when times are tough. Such pervasive influences appear to be the norm for megafauna, which means that bygone big animals were critical cogs in the wheels of North American ecosystems.
Those critical cogs are also missing from North Americans’ psyches. While we often fear them, we love megafauna. Anthropologist Paul Shepard wrote at length about our deep relationship with large animals, and how that relationship extends back tens of thousands of years. He believed there are important reasons why children’s books are filled with large animals. Given that children in the U.S. now spend 80 percent of their free time in front of television and computer screens, what are the psychological consequences to North Americans of losing touch with flesh-and-blood versions of the continent’s bygone megafauna?
The consequences to North Americans of losing such a colossal component of our natural heritage are rarely considered. Restoring megafauna to this continent will mean risking unexpected consequences. Some of those risks can be mitigated with sound science; others will be surprises revealed only by trial and error. Yet in the coming century, by default or design, our society will decide what and how much biodiversity we will coexist with. We now live in a world of decaying ecosystems, where humans increasingly lack any relationship with nature. Meanwhile, biodiversity conservation is focused on managing extinction instead of actively restoring natural processes. Maybe bringing megafauna back to North America could jumpstart a more proactive vision of biodiversity conservation, while also helping to reconnect people with nature.
My grandchildren likely will grow up in a world where videophilia trumps biophilia, and will almost surely know polar bears solely from DVDs. Perhaps we can do better, and our ecological history could help. Perhaps we can accept the risks and take the bold actions needed to bring back the megafauna. As biologist Geerat Vermeij stated, “A risk-free world is a very dull world, one from which we are apt to learn little of consequence.”