You are here:
BBC >
Science & Nature >
Prehistoric Life >
Monsters We Met >
Extinctions and Evidence
 |
 |
|
100,000 years ago, Homo sapiens first ventured out of Africa. The world they entered was the domain of giants: monstrous marsupials, huge eagles, savage short-faced bears and the terrifying 5.5 metre long ripper lizard, Megalania.
These monsters now exist only in our imagination or as long dead bones in a museum. In some areas of the world over 70% of large mammals became extinct around the time that humans arrived on the continent. But why? Was it man's arrival or was it coincidence?
What are the real answers to the mystery of the missing megafauna?
|
|
|
Some scientists believe there is damning evidence that humanity hunted the megafauna to extinction. The 'overkill' hypothesis holds that the megafauna vanished only a few centuries after the arrival of man and that hunting was the primary cause of the extinctions, for the following reasons:
 only the larger animals disappeared
there is archaeological evidence of human hunting
animals had survived previous times of climate change
The dinosaur extinctions
There have been many mass extinctions throughout geological history, the most well-known being the disappearance of the dinosaurs at the end of the Cretaceous Period. In analysing these events, scientists find that small, medium and large species all become extinct, although large animals (those over 44kg adult weight) always suffer the heaviest loss. These large animals are termed 'megafauna'.
Extinctions caused by humans
In contrast, the extinctions at the end of the Pleistocene seem to target large animals, with the small to medium ones escaping relatively lightly. Scientists that support the overkill hypothesis believe that this evidence points to humans as the culprits. The impact of human hunters on populations of large, slow-maturing, slow-breeding animals, such as mammoths and diprotodons, was bound to be far greater than any effect they might have had on small, rapidly breeding prey such as hares or squirrels. Therefore, the overkill theory seems to explain why only the megafauna died out.
|
|
|
|
 Messageboard
Do you have your own theories? Share your views on the Science messageboard. |
|
 |
|
 |
|
Man the hunter
