Recurrence pattern: every year on November 30.

Remembrance Day for Lost Species, also known as Lost Species Day, is observed worldwide every November 30. Established in 2011 by the founders of Feral Theatre and the Life Cairn memorial program, this volunteer-led campaign aims to explore the stories of species driven to extinction and emphasize the importance of conservation efforts. Participants engage in various activities such as creating art projects, lighting candles of remembrance, organizing memorial processions, and volunteering for conservation organizations. The day highlights the impact of human activities, including habitat loss and climate change, on biodiversity, with studies suggesting that a significant percentage of existing species may face extinction within a century. From 2011 to 2021, specific themes were suggested for events, focusing on notable extinct species, but since 2022, participants are free to choose their own stories to explore. The campaign is mainly managed by the Brighton-based arts charity ONCA and the co-directors of Feral Theatre.