Friday, August 21, 2015

Looking at Humans as ‘Super Predators’

The outrage following the killing of Cecil the lion by an American hunter last month was a stark reminder of a role that humans hold in nature: top predator.

We hunt not just lions and tigers, but also bears, wolves, deer and elk. We fish tuna, seabass, swordfish and salmon. We kill for food and sport.

But here’s a “what if?”: What if humans were considered as just another predator within the global ecosystem, rather than apart from it? How do our predatory habits compare with those of other top carnivores like lions, bears and sharks?

Those are the questions that Chris Darimont, a conservation scientist at the University of Victoria in British Columbia, set out to investigate. He and his colleagues wanted to put global hunting into context and quantify the impact of human predation.

The team combed through more than 300 research papers and constructed a database with more than 2,000 instances of human and nonhuman hunting and fishing. The biggest difference they found is that humans overwhelmingly kill adult prey while carnivores tend to hunt juveniles, for the simple reason that they are easier to kill.

This could be because humans prefer large trophies. “You will not hear a fisherman brag about the smallest fish of the day,” Dr. Darimont said.

The team also reported that commercial fisheries caught adult fish like cod and tuna at 14 times the rate that natural marine predators did. On land, humans and animal predators hunted herbivores like moose and deer at similar rates, but people killed large predators like bears and wolves at nine times the rate that these carnivores killed each other.

Dr. Darimont and his colleagues concluded that humans are “super predators” that hunt prey at unsustainable rates. They published their research Thursday in the journal Science.

- Nicholas St. Fleur

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