Once and Future Giants: What Ice Age Extinctions Tell Us About the Fate of Earth's Largest Animals
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Until about 13,000 years ago, North America was home to a menagerie of massive mammals. Mammoths, camels, and lions walked the ground that has become Wilshire Boulevard in Los Angeles and foraged on the marsh land now buried beneath Chicago's streets. Then, just as the first humans reached the Americas, these Ice Age giants vanished forever.
In Once and Future Giants, science writer Sharon Levy digs through the evidence surrounding Pleistocene large animal ("megafauna") extinction events worldwide, showing that understanding this history--and our part in it--is crucial for protecting the elephants, polar bears, and other great creatures at risk today. These surviving relatives of the Ice Age beasts now face the threat of another great die-off, as our species usurps the planet's last wild places while driving a warming trend more extreme than any in mammalian history. Deftly navigating competing theories and emerging evidence, Once and Future Giants examines the extent of human influence on megafauna extinctions past and present, and explores innovative conservation efforts around the globe. The key to modern-day conservation, Levy suggests, may lie fossilized right under our feet.
the American West. Photo courtesy of Page Museum and Los Angeles Natural History Museum. I first began reporting on the Pleistocene extinctions in 1999, when a paper published in Science claimed that the demise of Australia’s giants had been triggered by ancient Aborigines wielding fire sticks.2 The intensity of the resulting controversy, and its obvious relevance to pressing issues in modern ecology and conservation, captivated me. So did the players in the debate. Visiting with them was like
populations on Jasper Ridge died out in the 1990s, an outcome made inevitable by fragmentation of the butterfly’s habitat and speeded up by the impacts of climate change. Checkerspot larvae feed on only two kinds of native plants, plantain and owl’s clover. Larvae hatch from eggs in spring, feed voraciously, and then enter diapause, a hibernation in which they wait out the heat of the summer. Unless enough fresh, nutritious fodder is available, larvae cannot grow enough to survive diapause. In
plan controlled burns that run across multiple ranch boundaries. They supported a decade-long study of the relationships among cattle, vegetation, fire, and native small mammals, run on 9,000 acres of the Diamond A Ranch, and are replacing their old-fashioned fence lines with new barriers that allow wildlife to pass but still contain cattle. Some of the founding members, like Bill McDonald, heir to a century-old family ranch, have long been rotating their herds to rest pastures; the group
consummate skill. A lion that might contemplate a visiting tourist as a snack will flee at the sight of a Maasai. Despite the vast numbers of wildlife, face-to-face conflicts with animals are few, because the Maasai have mastered the process of living among them. It is a life completely alien to North Americans. “What you call the wild in the U.S.,” says Western, “is home to the Maasai. It’s the oldest cattle ranch on earth.” For all the impala, giraffe, and other fantastic beasts, most of the
Timothy F. Flannery, Linda K. Ayliffe, et al. (2001). “New ages for the last Australian megafauna: continent-wide extinction about 46,000 years ago.” Science 292: 1888–92. 9 Prideaux, Gavin J., John A. Long, Linda K. Ayliffe, John C. Hellstrom, Brad Pillans, Walter E. Boles, et al. (2007). “An arid-adapted middle Pleistocene vertebrate fauna from south-central Australia.” Nature 445: 422–25. 10 Trueman, Clive N. G., Judith H. Field, Joe Dortch, Bethan Charles, and Stephen Wroe (2005).