After Invading North America, Promiscuous Coyotes Look Southward
A hundred years ago, it would have been scary if a wild coyote wandered into a backyard in New York or Maine. That’d still be scary now, but definitely not unexpected. Over the past century, a recent ZooKeys study shows, coyotes have crept into every corner of North America, partially because we’ve cleared paths for them and partially because of their very fluid sexual preferences. Now, scientists write, they have their sights set on a whole new continent.
Coyotes already owned a lot of America to begin with — far more than we once estimated, write the North Carolina Museum of Natural Sciences and North Carolina State University scientists in their paper. Questioning the validity of early maps showing that coyotes lived only in America’s central deserts and grasslands, the team dug through archaeological records and fossils dating from 10,000 years ago to the late 1800s, producing a new map of coyote territory during the Holocene. It turns out coyotes had already taken over California and the arid deserts of the southwest as well.
But even that wasn’t enough for the promiscuous canines. After the 1920s, the team writes, the coyote population’s annexation of America went full tilt, paving the way for all of our present-day issues with the predatory species.
Analyzing museum specimens, peer-reviewed reports, and game department records from 1900 to 2016, the team mapped the spread of coyotes from their late-1800s habitats to their far larger, present-day territory. “Coyote expansion began around 1900 as they moved north into taiga forests, east into deciduous forests, west into costal temperate rain forests, and south into tropical rainforests,” they write in the paper.
Humans are to blame, at least partially. By clearing forests to make way for new settlements, we’ve fragmented their habitats, forcing them to seek out new places to hunt and live. But the coyotes, the team writes, seem well-equipped to make the most of a bad thing.
As they’ve been forced into new environments, they’ve run into new types of wildlife — distantly related canines, like wolves (C. lupus, C. lycaon, and C. rufus) and even domestic dogs. The coyotes, strangers in new lands, were constantly at a disadvantage relative to these animals, whose genomes were better-adapted to their environments. But rather than compete with them, the coyotes found a brilliant compromise: Have sex with them so their offspring could have the best of both worlds.
“Additionally, hybridization of coyotes with wolves and domestic dogs in eastern North America introduced new genotypes that may have promoted colonization and survival in eastern habitats,” the researchers write.
Now that the coyotes have taken over the north and east, they appear to be setting their sights on the south. They’ve already been seen crossing the Panama Canal, suggesting they’re well on their way. The final frontier between North and South America is the Darièn Gap, a huge swath of undeveloped swampland and forest in Panama. If the coyotes manage to clear that, they’ve got a whole continent of South American savannah to infiltrate: “[This] barrier may be more permeable than previously thought, especially along the coastlines, raising concerns that coyotes might reach South America in the near future,” the team writes.
There’s little doubt that coyotes will continue their spread southward, especially as people in the region continue to build roads and clear forests for agricultural purposes. How they will affect the local ecosystem remains to be seen, as the authors aren’t sure whether South American predators will be able to keep coyotes and their hybrid offspring in check. Given their impressive track record, coyotes may well prevail: After all, if they can’t beat them, they may very well just hook up with them instead.