Coyotes can habituate to humans quickly and habituated parents pass this fearlessness on to their offspring, research finds.
Across North America, coyotes are moving into urban environments, and their human neighbors are having to adjust. A big question for wildlife researchers is how coyotes habituate to humans, which can potentially lead to conflict.
“Even if it’s only 0.001 percent of the time, when a coyote threatens or attacks a person or a pet, it’s national news, and wildlife management gets called in,” says first author Christopher Schell, an assistant professor at the University of Washington Tacoma. “We want to understand the mechanisms that contribute to habituation and fearlessness, to prevent these situations from occurring.”
Coyotes without wolves
The study, part of Schell’s doctoral work at the University of Chicago, focused on eight coyote families at the US Department of Agriculture’s Predator Research Facility in Millville, Utah. The research center started in the 1970s to reduce coyote attacks on sheep and other livestock.
“Parents became way more fearless, and in the second litter, so, too, were the puppies.”
Until the 20th century, Schell says, coyotes lived mostly in the Great Plains. But when people hunted wolves almost to extinction in the early 1900s, coyotes lost their major predator, and their range began to expand. With continuing landscape changes, coyotes are now increasingly making their way into suburban and urban environments—including New York City, Los Angeles, and cities in the Pacific Northwest—where they live, mainly off rodents and small mammals, without fear of hunters.
The new study seeks to understand how a skittish, rural coyote can sometimes transform into a bold, urban one—a shift that can exacerbate negative interactions among humans and coyotes.
“Instead of asking, ‘Does this pattern exist?’ we’re now asking, ‘How does this pattern emerge?'” Schell says.
How puppies learn
A key factor may be parental influence. Coyotes pair for life, and both parents contribute equally to raising the offspring. This may be because of the major parental investment required to raise coyote pups, and the evolutionary pressure to guard them from larger carnivores.
The new study observed coyote families at the Utah facility during their first and second breeding seasons. These coyotes grow up in a fairly wild setting, with minimal human contact and food scattered across large enclosures.
But during the experiment researchers occasionally placed all the food near the entrance of the enclosure and had a human researcher sit just outside, watching any approaching coyotes, from five weeks to 15 weeks after the birth of the litter. Then they documented how soon the coyotes would venture toward the food.
“For the first season, there were certain individuals that were bolder than others, but on the whole they were pretty wary, and their puppies followed,” Schell says. “But when we came back and did the same experiment with the second litter, the adults would immediately eat the food—they wouldn’t even wait for us to leave the pen in some instances.
“Parents became way more fearless, and in the second litter, so, too, were the puppies.”
In fact, the most cautious pup from the second-year litter ventured out more than the boldest pup from the first-year litter.
Fur samples
The study also looked at two hormones in the coyotes’ fur—cortisol, the “fight or flight” hormone, and testosterone. The second litter of pups had mothers who experienced more stress during pregnancy, due to the researchers’ presence during the experiment, so that may have affected their development in the womb. But hormonal changes do not seem to have been passed down in that way.
Instead, the fur samples showed that the bolder pups had higher cortisol levels in their blood, meaning they ventured to the food despite their fear of humans. Further work would confirm whether, as Schell suspects, the cortisol levels would decline over time as the coyotes began to discount the human threat.
“The discovery that this habituation happens in only two to three years has been corroborated, anecdotally, by evidence from wild sites across the nation,” Schell says. “We found that parental effect plays a major role.”
Since arriving at UW Tacoma, Schell has begun working with Point Defiance Zoo & Aquarium to launch the Grit City Carnivore Project, which will use infrared motion-capture cameras to track coyotes and raccoons throughout the region. It’s part of the Chicago-based Urban Wildlife Information Network, studying urban wildlife across the country.
Other coauthors of the paper in Ecology and Evolution are from the US Department of Agriculture’s Predator Research Facility in Utah; Franklin and Marshall College in Pennsylvania; the University of Chicago; and Chicago’s Lincoln Park Zoo. Support for the work came from the University of Chicago, the National Science Foundation, and the US Department of Agriculture.
Source: University of Washington
