Mammal Day in 2025 is Global Mammal Day, celebrated annually on October 5th, on observation.org and globalmammalday.com. People are encouraged to observe and record mammal sightings to help monitor their populations and raise awareness for their conservation

Each year on October 5th, people from all walks of life will come together to celebrate the richness and diversity of the mammals. Global Mammal Big Day will be more than a date—it'll be a growing movement to honor, protect, and advocate for mammals, large and small, across our planet.