Francis Quang-Hai Dinh spent his first summer at McGill University exploring Montreal parks on his bicycle, observing and documenting over 800 grey and black squirrels across nearly 200 green spaces from Mirabel to Saint-Bruno. What began as a simple undergraduate assignment evolved into a personal project to investigate how the city’s layout and waterways impact evolution subtly.
Dinh, who is now pursuing integrative biology at the University of Illinois Urbana-Champaign, discovered that the prevalence of black squirrels increases as you move further north. In areas just north of Laval, up to 40% of squirrels had black coats, compared to around 15% on the island of Montreal and only 2-3% on the south shore. The study attributed this trend primarily to temperature, as black coloration helps squirrels absorb heat more effectively in cooler climates.
Additionally, the study highlighted the role of forest cover in influencing squirrel coat coloration, noting that denser tree canopies provide a darker background where black squirrels are better camouflaged. Allison Roth, the senior author of the study and an assistant professor at the University of Missouri, emphasized that urban environments like Montreal offer unique conditions for studying evolutionary changes in wildlife due to their diverse neighborhoods and distinct geographic features like waterways.
The research, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” delves into how urbanization impacts wildlife on a neighborhood level, challenging the notion that human development alone drives evolutionary changes in city animals. The study underscores that urban sprawl alters local temperatures, reduces tree cover, and creates natural barriers like riverways, all of which indirectly influence squirrel melanism.
The findings of this study are part of a special feature by five ecology journals that explore how researchers leverage data and collaboration to address significant ecological inquiries. Dinh reflected on his experience, noting how it has changed his perspective on wildlife and the coexistence of nature within urban settings. He emphasized that despite human modifications, wildlife will persist and adapt to their environments.