Researchers in Montreal have discovered that the coat colors of eastern gray squirrels are influenced by local environmental conditions. A study published in the Journal of Animal Ecology examined how the squirrels’ fur color varies across the city's parks. The findings suggest that factors like urbanization, the density of tree cover, and the presence of the St. Lawrence River and its tributaries affect the distribution of gray and black (melanic) squirrels. This research adds to the growing understanding of how urban environments shape wildlife traits. Francis Quang-Hai Dinh, an undergraduate student at McGill University and lead author of the study, observed more than 800 squirrels in nearly 200 parks around Montreal during his free time. The researchers also gathered data from park surveys and citizen science contributions, which allowed them to collect a broad and detailed dataset. They found that gray-coated squirrels were most commonly seen in the city, while black squirrels were more frequent in areas with cooler winter temperatures and more tree cover. This may be because darker coats can absorb more heat, providing an advantage in colder climates. Interestingly, black squirrels were less common in more urbanized parts of Montreal, which is different from patterns observed in other cities. The researchers noted that this finding needs further investigation. The study highlights how wildlife can adapt to environmental conditions at a very local level. Cities are not uniform environments, but rather complex landscapes where differences in neighborhoods and geographic features like rivers can influence how animals evolve and adapt over time. Allison Roth, the study's senior author and now an assistant professor at the University of Missouri, pointed out that people often think of cities as a single type of environment. However, the study shows that the conditions animals experience can vary significantly from one neighborhood to another. These local differences, along with natural barriers such as rivers, can influence how wildlife populations evolve. As a result, researchers must look beyond simple comparisons between urban and rural areas to fully understand how animals adapt to cities. The study was featured in a special collection across five ecology journals that focus on using large, open-access datasets and collaborative research methods to address major ecological questions. Dinh emphasized that the project demonstrates how scientific discoveries can be made using accessible resources and that meaningful research can happen right in one's own neighborhood.