Survival of the fittest. Nature has always and forever will play a predator/prey game on everything. I guess for humans the biggest excalation of this is war (not that it doesn't happen with other animals, ect... on a smaller scale). What doesn't make us extinct just makes us stronger. =)

I myself get really tired of theese "one" sided doucmenatarys. I guess the only way to trust any of it is to see it with your own eyes.