The Hawaiian hoary bat or ʻōpeʻapeʻa (Lasiurus semotus) is an endangered species of hairy-tailed bat (family Vespertilionidae) that is endemic to the Hawaiian Islands. Until 2015, they were considered a subspecies of the hoary bat, the most widespread bat in the continental United States. However, recent molecular research has shown that they form a distinct species. Since the continental hoary bat is also found on the islands, the Hawaiian hoary bat is now one of just three species of mammal that is endemic to the islands, the third being the Hawaiian monk seal. It is a federally listed endangered taxon of the United States.