Saturday, 18 February 2012

Humans,the biggest predator

Super-predatory humans
Predators have roamed the planet for 500 million years. The earliest is thought to be some type of simple marine organism, a flatworm maybe or type of crustacean, perhaps a giant shrimp that feasted on ancient trilobites. Much later came the famous predatory dinosaurs such as T. rex, and later still large toothed mammals such as sabre toothed cats or modern wolves. But one or two hundred thousand years ago, the world’s most powerful predator arrived. Us.
We lacked big teeth or sharp claws, huge tentacles or venomous bites. But we had intelligence, and the guile to produce tools and artificial weapons. And as we became ever better hunters we started harvesting animals on a great scale. We wiped out the passenger pigeon, the dodo, the great herds of North American bison. Last century we decimated great whale populations. Today the world’s fishing fleets routinely take more fish than scientists say is sustainable, leading to crashes in cod numbers for example, while people kill more large mammals in North America than all other causes put together. But out of our mass consumption of the world’s fauna appears a curious conundrum. Predators and prey are normally locked in an evolutionary arms race. As predators evolve to run faster, their prey too is selected to become fleeter of foot. As predators evolve sharp teeth, herbivores evolve horns for protection. Some carnivores hunt in packs, so their prey form defensive herds. But animals don’t appear to have evolved defences against us. Which raises the question why?

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