Richard Collins: Stress in the city — for animals as well as people
Inner Levels, Than Therefore Residues, Or Has Stress Study Have Areas Found Living Relatively Higher That Cortisol Higher The In And Leafy Coyotes A Living Areas Suburbs Natural Ones City In
Uneasy lies the head that wears a crown.
Being top dog seems glamorous but, as a study just published shows, it has its downside. Responsibilities come with kingship — noblesse oblige.
Coyotes are members of the dog family. Every male coyote longs to become the boss. As the alpha male, he will get to father all the pups of his pack. But, as Oscar Wilde said: "When the gods wish to punish us, they answer our prayers." The alpha male must stake out his pack’s territory and defend it against rivals, while constantly watching his back.
In April 2007, a coyote slipped quietly into a fast-food restaurant during lunch hour in Chicago’s business district. ‘Adrian’ was captured and sent to an animal rehabilitation centre. He caused a media stir at the time, but such an incident would be less remarkable today. Coyotes, like urban foxes in Ireland, are now established residents in Chicago and other American cities.
A 2006 report entitled ‘Thriving under our noses, stealthily; coyotes’ claimed that there are up to 2,000 of these canids living in the Chicago area. The new residents kill rats and mice and so are tolerated by people, although their nocturnal serenades of howls and yaps are not to everyone’s musical taste.
Living in cities is stressful for people. Is it equally so for urban wild animals, scientists at Ohio State University asked?
Chronic stress is difficult to quantify but cortisol, a hormone released when stress is experienced, can leave a trace in hair tissue for weeks or months.
City-dwelling coyotes were captured, tagged, and tracked in the Chicago area. Katie Robertson, lead author of a paper just published, clipped hair samples from the backs of 97 coyotes and measured their cortisol levels.
Some of the animals had been found dead in the city but most were trapped alive. Microchipped and fitted with tracking devices, their subsequent movements were logged to determine their social status within packs.
As with people, coyotes living in inner city areas had higher cortisol residues, and therefore higher stress levels, than were found in ones living in the leafy suburbs or relatively natural areas.
.@HanceEllington, a @UFWildlife scientist at @UF_IFAS_RCREC, co-authored a new study with @OSUEnvironment researchers that suggests urban living puts stress on #coyotes. https://t.co/onlyLsDYDS
— UF IFAS Solutions (@UF_IFAS) August 22, 2023
Poverty is also a stress factor: undernourished animals recording higher levels. This was as expected, but a coyote’s stress also correlates with its social status. Coyotes living alone, and not members of a pack, seemed to suffer most from chronic stress.
That drop-out loners fare less well was expected but, surprisingly, cortisol levels were also high in top dogs. The results showed that alpha males lead more stressful lives than ordinary pack members or cubs.
Animals leaving packs to seek their fortunes, and hoping to establish their own packs, were also highly stressed. As they wandered searching for an area in which to set up shop, they would come into conflict with established packs and occasionally with people. Moving about is inherently dangerous for coyotes. Being struck by vehicles while crossing roads is a major cause of death. Some coyotes have even learned to look right and left before crossing a road.