Sick coyotes more likely to clash with humans

Coyotes have been encroaching more frequently on North American cities over the last two decades, but researchers haven’t been sure why. Now a new study suggests that the animals’ health may be a factor. Sick coyotes are more likely to roam developed areas and eat people’s discarded food, leading to more encounters with humans.

The researchers studied 19 coyotes captured in Edmonton, Canada, where reports of coyote sightings are common. The team attached a GPS collar to each animal, collected hair samples, and checked the coyotes for signs of a disease called sarcoptic mange. Animals with this condition typically lose hair and develop thickened skin and lesions.

The study authors then tracked the coyotes’ locations for an average of four months each. They also performed chemical analyses of the hair samples to estimate the amount of prey (such as deer and beavers), fruit, and anthropogenic food in the animals’ diets.

The sick coyotes ranged over areas nearly four times bigger than healthy coyotes did, the team reports in Proceedings of the Royal Society B. And the diseased animals were recorded in developed areas more than five times as often as healthy animals. The amount of fruit in the coyotes’ diets was similar, but the sick coyotes ate 87 percent less prey and 33 percent more “people” food than the healthy animals did.

The diseased coyotes may be scavenging compost piles, the authors speculate. Animals with sarcoptic mange aren’t as good at catching prey; eating low-protein compost may, in turn, suppress their immune systems. “[D]isease, poor nutrition or poor hunting ability could be exacerbated by the other, creating a ‘vicious circle’ of low-quality diet, poor body condition and disease susceptibility,” the researchers write.

The solution? Managers should try to keep wildlife disease levels in cities under control, the authors say. And instead of just killing off sick animals, people also could make an effort to hide compost and other garbage from roving coyotes. Roberta Kwok | 16 April 2015

Source: Murray, M. et al. 2015. Poor health is associated with use of anthropogenic resources in an urban carnivore. Proceedings of the Royal Society B doi: 10.1098/rspb.2015.0009.

Image © Rob McKay | Shutterstock