For tens of thousands of years, where humans go, animals are driven to extinction. We are the superpredator, killing animals—and adults ones at that—at a much higher rate than other predators. And it's not sustainable. So say researchers at the University of Victoria in the journal Science after examining more than 300 studies and 2,125 predator-prey interactions on both land and sea to learn how much the adult population of their prey dwindles in a given year. They found that humans "kill adult prey at much higher median rates than other predators (up to 14 times higher)." Removing so many animals in their reproductive prime has implications for future populations, both in terms of raw numbers that can survive and how species evolve to handle this extreme predation.
"We predicted that there would be difference, but we were surprised by the magnitude of that difference," lead author Chris Darimont tells the Los Angeles Times. He goes on to call our hunting strategy "problematic," as we tend to kill adults while other predators naturally tend to target the "younger, smaller, weaker members of a species. ... Typically, human hunters remove one in 5 large carnivores from the planet each year, and ... most large carnivores do not have the reproductive ability to withstand that sort of mortality." But not everyone is ready to toss in the rifle and rod. "I think it’s total rubbish," one ecologist tells Science magazine. In fishing, for instance, the human haul accounts for 40% of total natural predation, which is reasonable for feeding our huge population. Fishing less, in his view, is not an option, thus this new study is "fuzzing up what we mean by sustainability." (Are fish evolving to escape our nets?)