Humans Take Out More Wild Species Than Any Other Predator on Earth

This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

Some people may be picky eaters, but as a species we are not. Birds, bugs, whales, snails, we’ll eat them all. Yet our reliance on wild animals goes far beyond just feeding ourselves. From agricultural feed to medicine to the pet trade, modern society exploits wild animals in a way that surpasses even the most voracious, unfussy wild predator. Now, for the first time, researchers have attempted to capture the full picture of how we use wild vertebrates, including how many, and for what purposes. The research showcases just how broad our collective influence on wild animals is.

Previously, scientists have tallied how much more biomass humans take out of the wild than other predators. But biomass is only a sliver of the total picture, and researchers wanted a fuller understanding of how human predatory behavior affects biodiversity. Analyzing data compiled by the International Union for Conservation of Nature, researchers have now found that humans kill, collect or otherwise use about 15,000 vertebrate species. That’s about one-third of all vertebrate species on Earth, and it’s a breadth that’s up to 300 times more than the next top predator in any ecosystem.

The predators that give us the biggest run for our money, says Rob Cooke, an ecological modeler at the U.K. Center for Ecology and Hydrology and a co-author of the study, are owls, which hunt a notably diverse array of prey. The Eurasian eagle owl, for instance, is one of the largest and most widely distributed owls in the world. Not a picky eater, this owl will hunt up to 379 different species. According to the researchers’ calculations, humans take 469 species across an equivalent geographical range.

Yet according to Chris Darimont, a conservation scientist at the University of Victoria in British Columbia and a co-author of the study, the biggest shock isn’t how many species we affect but why we take them. The “ta-da result,” he says, “is that we remove, or essentially prey on, more species of animals for non-food reasons than for food reasons.” And the biggest non-food use, the scientists found, is as pets and pet food. “That’s where things have gone off the rails,” he says.

There is some nuance to this broad trend. When it comes to marine and freshwater species, our main take is for human consumption. For terrestrial animals, however, it depends on what kind of animal is being targeted. Mammals are mostly taken to become people food, while birds, reptiles and amphibians are mainly trapped to live in captivity as pets. In all, almost 75 percent of the land species humans take enter the pet trade, which is almost double the number of species we take to eat.

The problem is especially acute for tropical birds, and the loss of these species can have rippling ecological consequences. The helmeted hornbill, a bird native to Southeast Asia, for example, is captured mainly for the pet trade, or for its beak to be used as medicine or to be carved like ivory. With their massive bills, these birds are one of the few species that can crack open some of the largest, hardest nuts in the forests where they live. Their disappearance limits seed dispersal and the spread of trees around the forest.

Another big difference between humans’ influence on wild animals and that of other predators is that we tend to favor rare and exotic species in a way other animals do not. Most predators target common species, since they are easier to find and catch. Humans, however, tend to covet the novel. “The more rare it is,” says Cooke, “the more that drives up the price, and therefore it can spiral and go into this extinction vortex.”

That humans target the largest and flashiest animals, Cooke says, threatens not only their unique biological diversity and beauty, but also the roles they play in their ecosystems. Of the species humans prey on, almost 40 percent are threatened. The researchers suggest industrialized societies can look to Indigenous stewardship models for ways to more sustainably manage and live with wildlife.

Andrea Reid, a citizen of the Nisg̱a’a Nation and an Indigenous fisheries scientist at the University of British Columbia, notes that people have been fishing for millennia. “But the choices that shape industrial fishing,” she says, like how people consume fish that were caught far away from their own homes, “are what contribute to these observed high levels of impact on fish species.”

If we want wild species—fish and beyond—to survive, Reid says, we need to reframe our relationship with them, perhaps from predator to steward.

This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

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