This article was originally on Hakai magazine, an online publication about science and society in coastal ecosystems. Read more of these kinds of stories hakai magazine. com.
Some humans may be picky eaters, but as a species we are not. Birds, insects, whales, snails, we eat them all. But our dependence on wildlife goes far beyond feeding ourselves. From farm feed to medicine to the pet trade, modern society exploits wild animals in ways that surpass even the most voracious, no-nonsense wild predator. Now, for the first time, researchers have tried to get a full picture of how we use wild vertebrates, including how much and for what purposes. The research shows just how broad our collective influence on wildlife is.
Previously, scientists have counted how much more biomass humans get from the wild than other predators. But biomass is only a fraction of the big picture, and researchers wanted a better understanding of how human predatory behavior affects biodiversity. Analysis of data collected 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 a third of all vertebrate species on Earth, and it’s a width up to 300 times greater than that of the next apex predator in any ecosystem.
The predators that make us the most money, says Rob Cooke, an ecological modeller at the UK Center for Ecology and Hydrology and a co-author of the study, are owls, which hunt a particularly diverse range of prey. For example, the Eurasian eagle owl is one of the largest and most widely distributed owls in the world. This owl is not a picky eater and preys on up to 379 different species. According to the researchers’ calculations, humans take on 469 species across an equivalent geographic range.
But according to Chris Darimont, a conservation scientist at the University of Victoria in British Columbia and co-author of the study, the biggest shock isn’t how many species we’re affecting, but Why we take them. The “ta-da result,” he says, “is that we are removing or essentially hunting more species for non-food reasons than for food reasons.” And the largest non-food use, the scientists found, is as pets and pet food. “That’s where things went off the rails,” he says.
There is some nuance to this broad trend. When it comes to marine and freshwater species, our top choice is for human consumption. For terrestrial animals, however, it depends on what kind of animal is being targeted. Mammals are mostly used as food for humans, while birds, reptiles and amphibians are mainly caught to live in captivity as pets. In all, nearly 75 percent of the land species humans take with them come into the pet trade, which is nearly double the number of species we eat.
The problem is particularly acute for tropical birds, and the loss of these species could have far-reaching ecological consequences. The helmeted hornbill, a bird found in Southeast Asia, for example, is mainly caught for the pet trade or to use its beak as medicine or to be carved like ivory. With their huge beaks, 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 the spread of seeds and the spread of trees in the forest.
Another major difference between humans’ influence on wildlife and that of other predators is that we tend to favor rare and exotic species in a way that other animals do not. Most predators target common species as they are easier to find and catch. However, people tend to covet the novel. “The rarer it is,” says Cooke, “the more that drives up the price, which is why it can spiral and end up in this extinction vortex.”
According to Cooke, people’s focus on the largest and most striking animals threatens not only their unique biological diversity and beauty, but also the role they play in their ecosystems. Nearly 40 percent of the species that humans hunt are endangered. The researchers suggest that industrialized societies could look to indigenous stewardship models for ways to interact and live with wildlife in a more sustainable way.
Andrea Reid, a citizen of the Nisg̱a’a nation and an aboriginal fisheries scientist at the University of British Columbia, notes that humans have been fishing for millennia. “But the choices that shape industrial fishing,” she says, such as how people consume fish caught far from their own homes, “contribute to these perceived high levels of impact on fish species.”
If we want wild species, fish and other species, to survive, Reid says, we need to rethink our relationship with them, perhaps from predator to steward.
This article first appeared in Hakai magazine and is republished here with permission.