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08-20-2023

Think city life is stressful? Some coyotes would agree

City living is not just stressful for humans, but also takes a toll on wildlife. According to researchers at The Ohio State University, urban dwelling coyotes face unique challenges that are impacting their overall health. 

The team measured the concentration of the stress hormone cortisol in the hair of nearly 100 coyotes inhabiting the Chicago Metropolitan Area. 

Higher stress levels

The experts discovered that the animals residing in the most developed areas exhibited higher cortisol levels – a marker for chronic stress – compared to those in suburban or natural regions.

“This is the first mammalian carnivore that has been evaluated for stress in an urban environment. The city does present challenges for them, even though they’re really good at doing what they’re doing. This is helping us understand how well animals are adjusting to urban systems – or not adjusting to them,” said study lead author Stan Gehrt, a wildlife ecologist at Ohio State.

Factors such as poor body condition, linked mostly to sickness with mange, and specific social roles within the pack were associated with higher stress levels. But the relationship between these factors and urban living is not entirely clear.

The research, conducted by the Urban Coyote Research Project under Gehrt’s leadership, was recently published in the journal Science of the Total Environment

The project has been monitoring Chicago’s urban coyotes since 2000, collecting valuable biological samples and data on their behavior, movement, and reproductive success.

Complexities of urban life

First author Katie Robertson, who carried out the work as a PhD student at Ohio State, utilized hair samples from the animals for the analysis, providing an estimate of long-term stress. The hair samples were assessed for cortisol concentration, revealing key factors connected to higher stress.

The team’s hypothesis that coyotes in more urbanized Chicago areas would display higher stress levels was confirmed by the results. 

However, the findings also exposed further complexity in modern coyote life. Infections and environmental factors such as cold Chicago winters contributed to the stress, raising questions about the root causes.

Which coyotes are affected?

“The alphas are the dominant animals in their pack, so they’re the ones that are responsible for all of the territorial defense and they’re the only ones that are breeding,” said Gerht.

“So there’s a lot going on with the alphas, whereas the subordinates and the pups, they have a pretty easy life. Their parents are doing all the hard work and they’re just coasting a little bit. And that was actually reflected in the cortisol levels.”

Transients, on the other hand – adult coyotes that have left their parents but not yet established or joined a pack – have a different set of worries.

“Transients were right up there with the alphas in terms of stress. They don’t have to defend a territory, but they have to avoid getting attacked by resident coyotes – they’re going through territories on a constant basis – and are trying to avoid people and trying not to get hit by cars,” Gehrt said.

In 2014, Gehrt’s observations highlighted the adaptability of some urban coyotes, as they learned to look both ways before crossing streets. This new research contributes to an understanding of coyotes’ resilience and the inherent challenges they face.

Some coyotes adapt quite well

“We see them on a regular basis living in some pretty challenging areas, and it seems to me they’re adjusting quite well – their survival rates are high, and the food supply is great,” said Gerht.

“And that’s what we found, that there are trends related to higher stress, but there are also coyotes that are doing quite well in the city with fairly low stress levels – even alphas in some pretty intense environments.”

“Even without the urban system, this is the first free-ranging coyote population to be evaluated for stress. And we see there’s stress associated with their very complicated social system and a lot of rules they’re following – intrinsic sources of stress that other species don’t have to deal with. It’s an interesting look into another window of their lives.”

The study’s findings offer a fresh perspective on the complexity of wildlife adaptation in urban environments, prompting further exploration of how city life may be shaping the health and behaviors of various animal species. 

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