Pity the coyote. Too small to stand up to wolves. Trapped or shot by many people who consider it a nuisance.
While these canids are known for their cunning and ability to survive even in cities, it turns out that they aren’t so good at calculating whether it’s safer to take their chances with wolves or people.
As top-level predators such as wolves expand in places like the western U.S., animals further down the food chain sometimes seek refuge among people. But for coyotes and bobcats, new research shows the strategy is a deathtrap. Adaptable as they are, evolution doesn’t seem to have fully equipped these animals to navigate the Anthropocene.
This experiment in how an ecosystem responds to the return of a top predator began in 1995, when federal biologists released a handful of wolves into Yellowstone National Park and nearby Idaho wilderness. Those populations, plus immigrants from Canada, thrived. Today they number nearly 3,500 in the northern Rockies and Pacific Northwest.
The arrival of wolves transformed some landscapes, documented most clearly in Yellowstone. As they preyed on elk herds there, streams and surrounding vegetation rebounded after decades of overgrazing.
But outside the protective confines of national parks, less is known about what happens to ecosystems as a wolf pack moves in.
A group of scientists in Washington state investigated a piece of this puzzle by looking at behavioral changes among bobcats and coyotes when they find themselves sharing a neighborhood with the largest of carnivores – wolves and cougars. (Cougars were present in the state throughout the 20th century, unlike wolves.)
They tracked the fates of 35 coyotes and 37 bobcats fitted with satellite-tracking collars in parts of northern Washington that mix remote, uninhabited mountains with small towns, farms and highways.
The data revealed that in places where wolves and cougars were abundant, coyotes and bobcats gravitated toward places with twice as much human presence, the scientists reported May 18 in Science.
“That indicated to us that coyotes and bobcats likely perceived these large carnivores as a greater threat to them than people,” said Laura Prugh, a University of Washington wildlife ecologist who worked on the study.
The phenomenon, dubbed the “human shield,” has been seen before. In just one example, moose in Yellowstone shifted toward giving birth near roads as the number of grizzly bears (which tend to avoid roads) increased.
But Prugh’s work showed that in the case of coyotes and bobcats, gambling on safety with humans was a losing bet. Of the 24 coyotes that died, 14 were at the hands of people (13 shot and one roadkill). None were killed by wolves. Of the 18 dead bobcats, people killed 11. All told, a coyote was 3 times more likely to die at the hands of a human than in the jaws of a carnivore, the researchers found. For a bobcat, the odds were even higher at 3.8 times.
The scientists aren’t sure what drove these animals to choose a more deadly home. It’s possible the millennia-old fear of their natural rivals trumped the novel dangers of pavement and high-powered rifles. It’s also possible the benefits of living next to people outweighed the deadly downsides. For instance, easier access to human food might enable bobcats or coyotes to have more offspring.
Whatever the reason, “their strategy of avoiding those large carnivores backfired by bringing them into contact with a much more effective predator,” said Prugh. “Us.”
Prugh, et. al. “Fear of large carnivores amplifies human-caused mortality for mesopredators.” Science. May 18, 2023.
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