Ratites And Flightless Birds

This group gathers Birds subcategory members belonging to the ratites, a set of large, flightless birds that lack the deep, keeled breastbone other flying birds use to anchor their flight muscles, leaving the sternum comparatively flat. It spans the ostrich, the largest and fastest-running living bird, native to the open plains of Africa, the emu, Australia's own large flightless runner, the cassowary, a powerful, dangerous rainforest bird of New Guinea and northern Australia armed with a sharp inner claw, and the kiwi, a small, nocturnal, almost wingless New Zealand bird that hunts largely by smell using nostrils placed at the tip of its unusually long bill, an arrangement unique among birds. Despite their shared flightlessness and their once-assumed status as one another's closest relatives, molecular studies have shown the ratites are not a single, cleanly unified lineage in the way their similar body plan once suggested, each having lost flight independently or through a more complicated shared history still being worked out.