World Otter Day is observed worldwide every last Wednesday of May to highlight the conservation status of otters, as over half of the 13 extant species are classified as threatened by the International Union for Conservation of Nature (IUCN). The event, coordinated by the International Otter Survival Fund (IOSF), began in 2009 as Otterly Mad Week, evolved into International Otter Awareness Day in 2014, and became World Otter Day in 2016. Participants engage in various activities such as visiting local zoos or aquariums, donating to otter charities, and organizing community events. The day aims to educate people about the ecological role of otters, the threats they face—including pollution and habitat loss—and the importance of their conservation. Additionally, the IOSF offers grants for small World Otter Day events to further promote otter protection. Social media campaigns using hashtags like #WorldOtterDay also encourage public participation and awareness.