While most of North America's wild mammals are losing their range, coyotes have been expanding across much of the continent since 1900. This 'great migration' is well documented at the local and state level, but it wasn't until recently that scientists were able to piece together all of the information into a coherent story.
In a new study, researchers assert that the canine predators have been offered room to expand thanks to human activity like farming and forest fragmentation, along with hybridization with other species. And as settlers chopped forests and raised huge ranches, they not only opened a corridor for coyotes to migrate out of their western United States historical range, they also culled large predators like pumas and wolves. Humans controlled these large predators for their own protection and that of their livestock, but in doing so they've set the table for a major coyote expansion across the whole nation that continues to this day.
That's not to say that coyotes haven't had their fair share of persecutions. Thousands of people have marshaled guns and set up traps specifically to hunt them down, but the coyote is a very resilient species. They eat whatever they can find, even if it's garbage, and are sneaky animals that know how to avoid peril. Speaking to the Washington Post, Stanley D. Gehrt, an Ohio State University professor and wildlife ecologist who runs the Urban Coyote Research Project, said that coyotes “are extremely flexible and adaptable to different kinds of environments … they’re generalists for sure, so generalists tend to do pretty well in cities, but they also benefit once they move into cities."
The new study was published by researchers led by Dr. Roland Kays, who is the head of the Biodiversity Lab at the North Carolina Museum of Natural Sciences. Kays and colleagues studied archaeological and fossil records in order to map the original range of coyotes, and then plot the predators' range expansion across the continent from 1900 to 2017.
The team inspected more than 12,500 records spanning the past 10,000 years. The analysis showed that the original assumption that ancient coyotes had been limited to central deserts and grasslands was incorrect. Instead, the evidence points to the fact that the historical coyote range was much broader, spanning western regions of the continent for thousands of years. A turning point where coyote expansion seems to have picked up a lot of steam was identified around the year 1920.
According to Kays, coyotes are also migrating to Central America after crossing the Panama Canal. Remarkably, some individuals have been spotted approaching the Darien Gap -- the heavily forested region separating North and South America. Soon, the coyote could also become a South American species.
“The expansion of coyotes across the American continent offers an incredible experiment for assessing ecological questions about their roles as predators, and evolutionary questions related to their hybridization with dogs and wolves,” said study lead author James Hody.
“By collecting and mapping these museum data we were able to correct old misconceptions of their original range, and more precisely map and date their recent expansions.”
“We hope these maps will provide useful context for future research into the ecology and evolution of this incredibly adaptive carnivore.”
The authors say that controlling coyote populations is and will continue to be very difficult, but that doesn't mean that their findings should be taken as justification for authorities to start a massive culling process. In all likelihood, that might not even work. "The one thing that will reduce coyote numbers are wolves," said Kays. Instead, the researchers advise that people should stop making artificial food sources available to coyotes and keep their pets supervised.
The study is published in the journal ZooKeys.
