Francis Quang-Hai Dinh spent his first summer at McGill University cycling around Montreal’s parks in search of squirrels. Covering nearly 200 green spaces from Mirabel to Saint-Bruno, he meticulously observed and documented over 800 grey and black squirrels. What began as a university task soon evolved into a personal project aimed at uncovering how the city’s layout and meandering waterways influence evolution.

Expressing his growing fascination, Dinh remarked, “I fell in love with them after I had started staring at them for long enough and just giving them enough thought. We don’t even think of squirrels as being animals. They’re practically just pests, but they are indeed wildlife.” Without access to a car and limited public transportation options in suburban areas, Dinh relied on his bicycle to reach distant locations, becoming the sole researcher known to manually survey squirrels park by park across the region.

Dinh’s findings revealed that approximately 12% of Montreal’s squirrels are black on average. However, as he ventured further north, the prevalence of black squirrels increased significantly. In areas just north of Laval, he discovered that up to 40% of squirrels exhibited black coloring. On Laval Island, around 20% were black, compared to 15% on Montreal Island and merely 2-3% on the south shore of Montreal. This phenomenon was attributed primarily to temperature variations, with black squirrels benefiting from their color’s enhanced heat absorption capacity.

Moreover, the study highlighted the impact of forest cover on squirrel populations, noting that denser tree canopies create darker backgrounds where black squirrels blend in better. Allison Roth, the study’s senior author and an assistant professor at the University of Missouri, emphasized that the research focuses on using squirrels as a model to explore how urban environments drive evolutionary changes.

Roth explained the significance of Montreal’s distinctive geographical features, such as the St. Lawrence River and its tributaries, in creating micro-environmental variations that influence genetic and physical adaptations within animal populations. She underscored that urban areas, like Montreal, present diverse neighborhoods with varying tree cover levels and natural barriers, shaping evolutionary processes in wildlife.

The study, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” challenges the conventional view that human development alone drives evolutionary changes in urban wildlife. It highlights the intricate interplay between urbanization, local temperature shifts, tree cover reduction, and natural barriers, like riverways, in shaping wildlife adaptations.

The research, featured in a special publication by five ecology journals, underscores the importance of data-driven collaboration in addressing significant ecological questions. Reflecting on his experience, Dinh noted a shift in his perspective towards wildlife, emphasizing the coexistence of nature and urban environments. He remarked, “We have this kind of dichotomy that city and nature are two completely separate things. And yet the reality is wildlife will continue to live and to persist despite whatever modifications we bring to it.”