Francis Quang-Hai Dinh spent his first summer at McGill University exploring Montreal’s parks on his bicycle, in search of squirrels. He visited nearly 200 green spaces from Mirabel to Saint-Bruno, meticulously observing and documenting over 800 grey and black squirrels. What began as a student project quickly evolved into a personal mission to understand how the city’s layout and waterways influence evolution.

Dinh, who is now studying integrative biology at the University of Illinois Urbana-Champaign, relied on his bike due to limited public transportation options in suburban areas. His hands-on approach made him the sole researcher known to conduct manual squirrel surveys park-by-park across the region.

His findings revealed that approximately 12% of Montreal’s squirrels are black on average, with a higher prevalence of black squirrels as he ventured further north. In areas just north of Laval, he discovered that up to 40% of squirrels had black coats, while on the island of Laval, this figure was around 20%. On the island of Montreal, it stood at approximately 15%, dropping to only two to three percent on the south shore.

The study attributed this variation to temperature and forest cover, with cooler climates favoring black squirrels due to their superior heat absorption capabilities. Additionally, denser tree canopies in certain areas provided better camouflage for black squirrels.

Allison Roth, the study’s senior author and a University of Missouri assistant professor, emphasized that urban environments play a significant role in driving evolutionary changes. Montreal’s diverse neighborhoods, varying tree cover levels, and natural boundaries like waterways create unique environmental conditions that can lead to genetic and physical adaptations within animal populations.

The research, titled “Fine-scale spatial variation in eastern grey squirrel melanism across a complex urban landscape,” offers insights into how cities influence wildlife evolution on a neighborhood-specific basis. Contrary to previous beliefs that human development solely drove these changes, the study highlights that urban sprawl, temperature fluctuations, and natural barriers all contribute to the evolutionary process.

As the study sheds light on the intricate relationship between cities and wildlife, Dinh reflected on how his perspective on nature has shifted. He emphasized that despite urbanization, wildlife will persist, challenging the notion that city and nature are separate entities.