Wild Northern Map Turtle (Graptemys geographica) can live at least half a century in Ontario

Turtles exhibit remarkable longevity but estimating the age of wild turtles is challenging. We report observations of Northern Map Turtle (Graptemys geographica) in Opinicon Lake, Ontario, that demonstrate lifespans exceeding 50 years. Since 2003, the Opinicon Lake population has been continuously monitored through a capture–mark–recapture study. However, earlier marking efforts in the 1970s provided an opportunity to assess the minimum longevity of several individuals. One female, marked in 1978 at an estimated age of 10 years, was recaptured multiple times between 2004 and 2025 revealing an estimated age of 57 years. Seventeen additional turtles displaying marks consistent with tagging from the 1970s were also recaptured between 2006 and 2025, suggesting minimum ages ranging from 31 to 55 years. The considerable longevity of these turtles in Ontario has important implications for their conservation.