Narrator: This is Science Today. As predators, humans are a dominant evolutionary force. In fact, a University of California, Santa Cruz analysis has found that human predation is accelerating the rate of observable trait changes in species by 300 percent above what's observed within natural systems. Environmental studies researcher, Chris Darimont, who led the study, says that's why humans are referred to as super predators.
Darimont: We exploit at far higher levels than natural predators, whereas a predatory fish or something like a hawk or something like a wolf might take ten percent of its prey per year. Humans on average take far, far higher proportions of prey every year. The second reason why we refer to humans as super predators is that we exploit incredibly broad niches and what I mean by that is that we prey on just about everything edible on this planet. What we can take from this study is not that hunting and fishing are necessarily bad actions - the way in which we hunt and fish are causing very serious and potentially irreversible changes.
Narrator: For Science Today, I'm Larissa Branin.