Hunters to blame for extinction

2010-11-27 22:07

Chersky - During the last Ice Age, shaggy mammoths, woolly rhinos and bison lumbered across northern Siberia. Then, about 10 000 years ago - in the span of a geological heartbeat, or a few hundred years - the last of them disappeared.

Many scientists believe a dramatic shift in climate drove these giant grazers to extinction.

But two scientists who live year-round in the frigid Siberian plains say that man - either for food, fuel or fun - hunted the animals to extinction.

Palaeontologists have been squabbling for decades over how these animals met their sudden demise. The most persuasive theories say it was humanity and nature: Dramatically warming temperatures caused a changing habitat and brought a migration of men armed with deep-piercing spears.

No one knows for sure what set off global warming back then - perhaps solar activity or a slight shift in the Earth's orbit. But, in an echo of the global warming debate today, Sergey Zimov, director of the internationally funded Northeast Science Station, and his son Nikita say man was the real agent of change.

Ice retreated

For the Siberian grasses to provide nutrition in winter, they needed to be grazed in summer to produce fresh shoots in autumn. The hooves of millions of reindeer, elk and moose as well as the larger beasts also trampled choking moss, while their waste promoted the blossoming of summer meadows.

As the ice retreated at the end of the Pleistocene era - the final millennia of a 1.8 million yearlong epoch - it cleared the way for man's expansion into previously inaccessible lands, like this area bordering the East Siberia Sea.

Northeastern Siberia, today one of the coldest and most formidable spots on the globe, was dry and free of glaciers. The ground grew thick with fine layers of dust and decaying plant life, generating rich pastures during the brief summers.

When humans arrived they hunted not only for food, but for the fat that kept the northern animals insulated against the subzero cold, which the hunters burned for fuel, say the scientists. They may also have killed for prestige or for sport, in the same way buffalo were heedlessly felled in the American Old West, sometimes from the window of passing trains.

The wholesale slaughter allowed the summer fodder to dry up and destroy the winter supply, they say.

A system

"We don't look at animals just as animals. We look at them as a system, with vegetation and the whole ecosystem," said the younger Zimov. "You don't need to kill all the animals to kill an ecosystem."

During the transition from the ice age to the modern climate, global temperatures rose five degrees Celsius. But in Siberia's northeast the temperature soared seven degrees, in just three years, the elder Zimov said.

The theory of human overkill is much disputed. Advocates of climate theory say the warm wet weather that accompanied the rapid melting of glaciers spawned birch forests that overwhelmed the habitats of the bulky grass eaters.

Adrian Lister, of the palaeontology department of London's Natural History Museum, said humans may have delivered the final blow, but rapid global warming was primarily responsible for the mammoth's extinction. It brought an abrupt change in vegetation that squeezed a dwindling number of mammoths into isolated pockets, where hunters could pick off the last herds, he said.

People "couldn't have done the whole job," he told AP Television News.

Shrinking numbers

Mammoths once ranged from Russia and northern China to Europe and most of North America, but their numbers began to shrink about 30 000 years ago. By the time the Pleistocene era ended they remained only in northern Siberia, Lister said.

As in millennia past, Sergey Zimov believes hunting is a problem today.

"I believe it's possible to increase the density of herbivores in our territory 100 times," says Zimov, who keeps a six-foot-long yellow-brown tusk of an 18-year-old female in a corner of his living room. "I say let's stop the poaching. Let's give freedom for animals."

  • andrewpottow - 2010-11-28 11:25

    Who pays these guys bills? seriously? Any palaeontologists for that matter? Firstly, its not science. Science is the study of the observable, not guessing what happened before we were able to observe and record it. Secondly, they're just guessing with an incomplete picture made up of a minimal base of evidence, they're paid to make assumptions and logically the more shit they stir up, the more they get paid in fame as well as money.

      Bryan Marcus Peters - 2010-11-29 00:14

      Andrew, you have a rather hazy view about what "science" is. The theory that "science"="observable" is, in its simplest form, known as logical positivism and has been discredited by philosophers and scientists for a few decades now. Are quarks and bosons perceivable by the human senses? Nope, but these sub-atomic particles are theories that arise as the best explanation for certain effects. Also it would be a brave person to state that human observation is direct and without some other innate (neurologically embedded) theory about how the natural world functions. Our vision, for example, actually has a blind spot (due to the optic nerve exiting the retina), but this blind spot gets filled in by our higher order cognitive processes to render our visual perception of the world as seamless. Some of the other aspects of "Science" are: 1) Coherence of the theory. Does the novel/new theory fit in with pre-existing theories and data? 2)Objectivity of the theory. How independent is the theory from bias? 3)Simplicity/Elegance of the theory. How economic is the theory? 4)Explanatory power of the theory. How wide is the scope of the theory compared to others? If you are truly interested in what "Science" is really about, I suggest you read: "What is this thing called Science" by Chalmers or "What Science Is and How It Works" by Derry. Until you’ve read the above books or some other suitable material, please refrain from making rather inane remarks on a matter that you do not fully understand.

      scipio - 2010-11-29 10:30

      Bryan, If you watch Natgeo you'll notice all the Bullcarp these so called scientist can come up with like for example Life after People. The predictions made has no scientific base or exploration around it. Most scientists are of a lazy breed, guessing their way through life, with most common folk taking it to heart. Sure it's inappropriate to question everything, but these scientist are no super Humans. The follow a Blueprint of previous scientists, contributing only there 2 cents worth. Every once in a while you do get a Legitimate scientist, but then again they wouldn't go into the study of mammoth extinction

      Bryan Marcus Peters - 2010-11-29 13:13

      Hail Scipio — you have made some sweeping generalisations. Although there are certainly some lazy and dishonest scientists (just as there are lazy, dishonest laypeople), I wouldn't go so far as to state that "most scientists are a lazy breed". Most of the technology and culture you take for granted are the labours of these "lazy scientists". Also National Geographic is "popular science": it acts as an intermediary between the hard science journals (which are generally unavailable to most non-scientists/academics) and the general public. As such, there is likely to be some problems when translating concepts from these journals to the public. A lot of science publications are rather dully written and entities such as Nat Geo and Popular Science try to glamour these up and this process isn't always successful. "Heisenberg's Uncertainty Principle", "Einstein's Theories of Relativity" and "Darwin's Theory of Evolution" are casualties of this process: many laypeople have erroneous perceptions of these theories. This is not to say that "Science" or rather, more accurately, "Academia" is perfect. It isn't. Money, vicious rivalry, politics and jostling for power, are all part of the equation. Funding, resources and jobs are scarce in academia. But the aspects of "Science" I mentioned previously (in reply to Andrew) combined with peer-review, and replication, help to prevent dishonest "Science". Every 2 cents do count. Rome wasn't built in a day: your namesake understood this well.

  • Kaspaas01 - 2011-01-17 15:22

    Poaching is a problem today, not hunting! Hunting creates revenue for the conservation and protection from animals against poachers. No hunting farm owner will allow hunting that reduces animals to the extent that he might lose his livelihood. Look at the boom of game numbers in the Eastern Cape due to the hunting industry during the last 10 years. This is due to proper game management principles.

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