New study shows humans are 'super-predators' having permanent impact on food web

Recent global outrage over trophy hunting has showcased just how vicious of a predator humans can be. But now, new research released this week in the journal Science offers sobering scientific evidence that proves that humans are indeed a new kind of indiscriminate super-predator, the likes of which the planet has never seen before. And if we continue our killing tendencies, we will be irreparably impacting the sustainability of the worldwide food web and even changing the course of evolution for countless species.

“Humans are one very unique predator and it’s our high rates of predation on adult age classes of prey that sets in motion all sorts of ecological and evolutionary effects that eventually harm humanity,” said co-author of the new study Chris Darimont, Hakai-Raincoast professor at the University of Victoria and science director with Raincoast Conservation in an interview with Yahoo Canada.

Over thousands of years the human species have evolved into hunter-gatherers, which have used increasingly deadly and more efficient weapons technologies – from spears to bullets to nets – that have allowed us to kill our prey and exploit animal population at rates that now far exceeds the impact of other predators, be they on land or sea.

High-tech hunting making huge dent in numerous species

Today we search for schools of herring from airplanes and using sonars, and can hunt wildlife on land using four-wheel drive trucks and snowmobiles. Scientists believe the focus on the harvesting of adults rather than juveniles, which most predators prefer, is related to our technological prowess that allows us to kill from a distance, without any threat to the hunter.

The authors undertook an exhaustive search of 2135 exploited wildlife populations that included both species of marine fish and terrestrial predators in all oceans and on all continents except Australia. What they found was humans take up to 14 times as much adult prey biomass as do other predators, particularly targeting those in their reproductive prime, with the most striking effects seen in our oceans.

This kind of over-exploitation by humans has also produced a loss of large carnivores, causing diseases to pop up in many herbivores that are valued by humans. At the same time, some populations of herbivores have exploded, stripping the environment of other lifeforms like insects and birds that are an integral part of a healthy ecosystem.

The authors found in the fishing industry, for example, that the healthiest, most reproductive and largest individuals from a population are often targeted, which can end up skewing and even removing certain desirable genetic traits from a species, such as the ability to grow large. Some species of fish have actually ended up shrinking in body size, and as a consequence produce fewer offspring. The end result, they warn, could very well put such selection pressures on an exploited wildlife population that the inherent natural variety in their gene pool could have a hard time bouncing back to healthy levels.

While Darimont is worried about the ocean’s fish populations, he says he is optimistic after observing the moral outage expressed globally following Cecil the lion’s death.

“It signals to me that society might no longer grant ‘social license’ to those that hunt not for food – because large carnivores are not edible – but for trophy,” says Darimont.

It’s because of these powerful and unique hunting practices that Darimont says makes humans the ultimate super-predator.

“Humans are the only predator that consistently and aggressively kills other predators,” he pointed out. “Also humanity’s impact on other prey, on evolutionary processes, like shrinking fish, and the ecosystem deserves the superlative.”

Can humans curb their predatory ways?

Non-human predators, like sharks and lions, stand as models of sustainable exploitation, says Darimont, because they don’t irreparably decimate their prey populations over ecological time scales.

He suggests taking a lesson from certain human cultures that are looking at the long term impacts on the environment and their prey as renewable resources. In terms of fishing, it would mean simply shift our harvesting preferences, for instance, to juvenile classes instead of constantly targeting adults.

This may be easier said than done, however. While some small African villages are already practicing this kind of sustainable fishing pattern very successfully locally, the reality is that it may be near impossible when it comes to implementing this new mindset worldwide in our multi-billion dollar fishing industry.

But large-scale changes, the team says, likely can start simply by cultivating a new tolerance for competing predators. Local communities, for instance, should have revenues tied to non-consumptive uses of wildlife such as ecotourism.

“In some cases, safeguarding large carnivores threatened by trophy hunting requires societal pressure to drive policy change or ensure better enforcement,” says Darimont.

“The moral outrage expressed globally over the death of Cecil the lion tells us that this time could be drawing closer.”