Martin-Prologue Twilight of Mammoths-1

Martin-Prologue Twilight of Mammoths-1 - PROLOGUE Imagine a...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: - PROLOGUE Imagine a world with only half the variety of large animals that we know today. Imagine an Africa with hyenas but no lions, an Australia with wom- bats but no koalas, a North America with elk but no bison. Imagine zoos and televised nature programs featuring rhinos without hippos, giraffes without gorillas, zebras without camels, leopards with- out cheetahs. The missing animals simply do not exist; we know them only from fossils. Without realizing it, we are in exactly this situation today. In what paleontologists have begun to call “near time,” the last 50,000 years, datable by radiocarbon, the world lost half of its 200 genera of large mammals (those weighing more than 45 kilograms or 100 pounds). Be- yond the living bears, bison, deer, moose, and other large mammals fa- miliar to us now, an additional 30 genera and over 40 species lived in North America, and even more in South America. Most of the Western Hemisphere’s charismatic large mammals no longer exist. As a result, without knowing it, Americans live in a land of ghosts. Some of these great creatures—the extinct megafauna—-appear in pop— ular museum displays in our large cities. Even the names of others are utterly unfamiliar to most of us. North America lost mastodons, gom- photheres, and four species of mammoths; ground sloths, a glyptodont, and giant armadillos; giant beavers and giant peccaries; stag moose and dwarf antelopes; brush oxen and woodland musk oxen; native camels 2 / PROLOGUE and horses; short—faced bears, dire wolves, saber-toothed and dirk- toothed cats, and an American subspecies of the king of beasts, the lion. After the extinctions, the mean body mass of North American mammals was the lowest it had been in 30 million years (Alroy I 999). The survivors of the big Wipeout are those large animals familiar to us now, such as bison, brown (grizzly) bears, cougars (mountain lions), deer, elk (wapiti), moose, musk oxen, and pronghorns. Most people re— gard these as defining “wild America.” They do not. To give so little at- tention to the dozens of big animals we have lost so recently simply sells North America short. Before extinction of our native big mammals, the New World had much more in common with an African game park than most of us realize. South America also lost heavily. Extinction struck many species of ground sloths, one monster weighing over 4,500 kilograms (10,000 pounds) (Farina, Vizcaino, and Bargo I 997). The biggest native herbi- vore in the New World tropics today is Baird’s tapir, which may reach 225—300 kilograms (about 500—650 pounds). Australia lost giant animals of its own. Though not as massive as the largest in the Americas, they included giant wombat-like creatures the size of rhinos, giant kangaroos larger than any of the living kangaroos, many other large marsupials, and even some oversized koalas and echid- nas. (Echidnas, or spiny anteaters, differ from all other mammals in that their shell—covered eggs are incubated and hatched outside the mother’s body.) ' If we could travel back just those 50,000 years—~a third of the age of our species in Africa, but a mere I/80,000th of the roughly 4.5-billion— year age of the Earth—~we would find ourselves in a “Quaternary zoo” far more spectacular and much richer in species of large mammals than any zoo that exists today. Any fan of modern wombats—muscular 4-foot-long marsupials re- sembling badgers with elongated koala faces—~would delight in seeing diprotodons, which looked like one-ton wombats. The diprotodons and their entire family suffered extinction over 40,000 years ago. Those who enjoy America’s modern armadillos would take particu- lar pleasure in the glyptodonts, another extinct family. The size and over- all shape of a giant tortoise or of a Volkswagen “beetle” (Hulbert 2001), glyptodonts were completely armored in bone and had long, muscular tails ending in a club or a mace-like cudgel, presumably used to beat off attackers. PROLOGUE / 3 We would gaze in awe at mastodons, mammoths, and gomphotheres, all relatives of modern elephants. The American display would also fea- ture several species of ground sloth, some of them as large as the mam- moths. The Shasta ground sloth was about the size of a large black bear. The public would flock to the viewing platform at feeding time, when buckets of this animal’s favorite vegetable, mallows in the hollyhock fam- ily, would attract patient mothers carrying their young on their backs. It would be harder to feed the biggest ground sloths, elephant—sized Megatb- erium, able to reach high into trees, pulling down branches with their long arms and heavy claws. Some paleontologists suspect they may also have been scavengers, eating carcasses of large dead animals. The carnivore displays would be equally impressive. The short—faced bear, Arctodus, exceeded all living bears in size and probably in speed. The famous saber—toothed cat (Smilodon) was about the size of today’s African lion, with curved 7-inch~long upper canines, while the canines of the scimitar cat (Homotberium) were “only” 4 inches long. Among the other carnivores were a subspecies of lion, Pant/06m leo atrox, as well as the dire wolf, Cam's dirus, along with the dhole, Cuon, a wild dog that survives in Asia. These are some of the more spectacular mammals we would see in a Quaternary zoo, side by side with our familiar bears, bison, and hippos. If the zoo included birds and reptiles, we would also see New Zealand’s moa—Io extinct species of flightless, hairy-looking birds, the largest of them bigger than ostriches. Among the wondrous Australian giants were fearsome monitor lizards weighing up to 150 kilograms (330 pounds); two terrestrial crocodiles; and a giant extinct python. All of these animals were present on the planet until well into the life- time of our own species. Why are they gone from the Earth today? In this book I argue that virtually all extinctions of wild animals in the last 50,000 years are anthropogenic, that is, caused by humans. To get our history right we need to know more about the extinctions of near time. And we need to give thought to reversing prehistoric extinctions when we have the chance. That leads us to the most controversial vista of them all, the contemplation of bringing back the elephants and representa- tives of other lineages that evolved over tens of millions of years in the Americas. ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern