of the tribe Monachini. The tribe was first conceived by Victor Blanchard Scheffer in his 1958 book Seals, Sea Lions, and Walruses: A Review of the Pinnipedia. The two genera of monk seals, Monachus and Neomonachus, comprise three species: the Mediterranean monk seal (Monachus monachus), the Hawaiian monk seal (Neomonachus schauinslandi), and the Caribbean monk seal (N. tropicalis), which became extinct in the 20th century. All three monk seal species were classified in genus Monachus until 2014, when comparison of the species' mitochondrial cytochrome b DNA sequences led biologists to place the Caribbean and Hawaiian species in a new genus, Neomonachus. Fossils of the Mediterranean and Caribbean species are known from the Pleistocene. The time of divergence between the Hawaiian and Caribbean species, 3.7 million years ago (Mya), corresponds to the closing of the Central American Seaway by the formation of the Isthmus of Panama. The divergence between Mediterranean seals and the New World clade was dated to 6.3 Mya ago. Fossils of a Pliocene species of monk seal, Eomonachus belegaerensis, have been found in Taranaki region of New Zealand. This could possibly place the origins of the group in the Southern Hemisphere. The only other fossil monk seal is Pliophoca etrusca, from the late Pliocene of Italy. Habitat The Hawaiian monk seal, as the name suggests, lives solely in the Hawaiian archipelago. Monk seals migrated to Hawaii between 4–11 Mya through an open-water passage between North and South America called the Central American Seaway. The Isthmus of Panama closed the seaway 3 Mya. The species may have evolved in the Pacific or Atlantic, but in either case, came to Hawaii long before the first Polynesians. When monk seals are not hunting or eating, they generally bask on the beaches; Hawaiian monk seals tend to bask on sandy beaches and volcanic rock of the Northwest Hawaiian Islands. The habitat of the Mediterranean monk seal has changed over the years. Prior to the 20th century, they had been known to congregate, give birth, and seek refuge on open beaches. Since sealing had ended, they have left their former habitat and now only use sea caves for such behavior. More often than not, these caves are rather inaccessible to humans due to underwater entries, and because the caves are often along remote or rugged coastlines. Scientists have confirmed this is a recent adaptation, most likely due to the rapid increase in human