Francis Quang-Hai Dinh spent his first summer at McGill University exploring Montreal’s parks on his bicycle, on a mission to study squirrels. He meticulously observed and documented over 800 grey and black squirrels in nearly 200 green spaces stretching from Mirabel to Saint-Bruno. What began as a student assignment evolved into a personal project to investigate how the city’s geography and waterways influence the evolution of its wildlife.
Dinh, who is now pursuing integrative biology at the University of Illinois Urbana-Champaign, relied on his bike to traverse suburban areas due to limited public transportation options. He became the sole researcher known to conduct manual squirrel surveys park-by-park across the region.
His research revealed that approximately 12% of squirrels in Montreal are black, with a higher prevalence of black squirrels in northern areas. In locations just above Laval, up to 40% of squirrels had black fur, while on the island of Laval, around 20% were black. Comparatively, the percentage dropped to only two or three percent on the south shore of Montreal. Dinh attributed these findings to temperature variations, with black squirrels benefiting from their color’s heat-absorbing properties.
Additionally, the study highlighted the role of forest cover in squirrel populations, where denser tree canopies create ideal camouflage for black fur. Allison Roth, the study’s senior author and a University of Missouri assistant professor, emphasized that the research aimed to use squirrels as a model for understanding how urban environments drive evolutionary changes. She noted that Montreal’s distinct neighborhoods, diverse tree cover, and natural boundaries, such as waterways, create unique environmental conditions that can lead to genetic and physical adaptations within animal populations.
Contrary to previous studies that compared urban and rural areas broadly, this research focused on neighborhood-level wildlife changes. It demonstrated that urban sprawl, temperature fluctuations, tree coverage reduction, and natural barriers like rivers all play significant roles in shaping wildlife adaptations. The study’s findings suggest that urbanization indirectly influences melanism in squirrels through environmental factors rather than as a direct outcome.
The research, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” will be published as part of a special feature in ecology journals emphasizing collaborative data-driven approaches to address ecological inquiries. Dinh reflected on his transformed perspective on wildlife, highlighting the coexistence of nature and urban environments despite human modifications.