The Caribbean monk seal, west Indian seal (Monachus tropicalis), or sea wolf, as early explorers referred to it, was a species of seal native to the Caribbean and now believed to be extinct. The Caribbean monk seals' main predators were sharks and humans. Overhunting of the seals for oil, and overfishing of their food sources, is the established reason for the seals' extinction. The last confirmed sighting of the Caribbean Monk Seal was in 1952 at Serranilla Bank, between Jamaica and Nicaragua. In 2008 the species was officially declared extinct after an exhaustive five-year search for the seals, conducted by the National Oceanic and Atmospheric Administration and National Marine Fisheries Service. Caribbean Monk Seals were closely related to the Hawaiian monk seals (Monachus schauinslandi), which live around the Hawaiian Islands, and are critically endangered, and Mediterranean monk seals (Monachus monachus), which are also critically endangered. An estimated 600 Mediterranean monk seals and 1,100 Hawaiian monk seals are alive in the wild. A collection of Caribbean monk seal bones can be found at the Tropical Crane Point Hammock Museum in Key Vaca.