单词	ratite
释义	ratite /ˈratʌɪt / Ornithology adjective (Of a bird) having a flat breastbone without a keel, and so unable to fly. Contrasted with carinate.When the ratite birds first roamed Gondwana, they could walk from any of the places where they later dwelt, to any other.... About 30 years ago, Joel Cracraft sketched out the central melodies of ratite evolution. They may well have been native to Africa - just one link in a continuous chain of ratite species that circled Gondwana until it broke up. noun Any of the mostly large, flightless birds with a ratite breastbone, i.e. the ostrich, rhea, emu, cassowary, and kiwi, together with the extinct moa and elephant bird.Other ratites, the elephant bird of Madagascar and the moas of New Zealand, have been extinct for several centuries, probably as a result of human hunting.... Moas were ratites, flightless birds considered the sister group of all other birds. Cassowaries are large ratites, and are among the largest birds in the world. Origin Late 19th century: from Latin ratis 'raft' + -ite1.
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