When coyote parents get used to humans, their offspring become bolder, too
March 11, 2019 by Hannah Hickey, University of Washington
Across North America, coyotes are moving into urban environments, and regardless of how they feel about it, urban residents are having to get used to some new animal neighbors. A big question for wildlife researchers is how coyotes habituate to humans, which can potentially lead to conflict.
Five-week-old coyote pups eat food rations during the experiment. These second-litter pups were born in 2013 to more-experienced parents, and were more likely to approach a human. Photo courtesy of the USDA National Wildlife Research Center. Credit: Christopher Schell
A study led by a University of Washington Tacoma faculty member, recently published in Ecology and Evolution, suggests coyotes can habituate to humans quickly and that habituated parents pass this fearlessness on to their offspring.
Figure 1
Conceptual diagram of potential scenarios in which parental habituation and offspring risk‐taking behavior are related to predictable cues of anthropogenic environments over time. Dots indicate risk‐taking behavior within fathers (black) and mothers (gray) over successive reproductive events, whereas pups (green) are separate litters. In (a) both mothers and fathers become habituated, and as a result demonstrate riskier behavior across reproductive bouts. If parental cues are a reliable signal of current environmental conditions, then it is predicted that pup risk‐taking will also increase. In (b) only a single parent becomes habituated to anthropogenic disturbance, with the other parent possibly selectively constrained. Second‐litter pups may exhibit slightly greater risk‐taking than their first‐litter siblings, although they may not differ statistically. And in (c), neither parent becomes habituated over time. In all scenarios, it is assumed that parental behavior is a reliable cue of environmental conditions that offspring use to fashion their behavior
"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," said first author Christopher Schell, an assistant professor at UW Tacoma. "We want to understand the mechanisms that contribute to habituation and fearlessness, to prevent these situations from occurring."
The study, done as part of Schell's doctoral work at the University of Chicago, focused on eight coyote families at the U.S. Department of Agriculture's Predator Research Facility in Millville, Utah. The research center was founded in the 1970s to reduce coyote attacks on sheep and other livestock.
Figure 2
Schematic depicting the general timeline and experimental design used to observe offspring traits of first and second litters. Foraging assays were performed 2–3 times per week from 5–15 weeks of age. At 15 weeks of age, pups were removed from their natal pens to enclosures independent of their parents
Until the 20th century, Schell said, coyotes lived mostly in the Great Plains. But when wolves were hunted 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.
These 7-week-old coyote pups walk through the research facility in Utah. Their mother, in front, carries a bone in her mouth. Photo courtesy of the USDA National Wildlife Research Center. Credit: Steve Guymon/National Wildlife Research Center
"Instead of asking, 'Does this pattern exist?' we're now asking, 'How does this pattern emerge?'" Schell said.
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 are raised in a fairly wild setting, with minimal human contact and food scattered across large enclosures.
"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.
The study was conducted at the Predator Research Facility in Millville, Utah. This 2011 photo courtesy of the USDA National Wildlife Research Center. Credit: Christopher Schell/National Wildlife Research Center
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 said. "We found that parental effect plays a major role."
Explore further: Coyotes becoming problem for urban areas
More information: Christopher J. Schell et al, Parental habituation to human disturbance over time reduces fear of humans in coyote offspring, Ecology and Evolution (2018). DOI: 10.1002/ece3.4741
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