Largest organisms is frequently poorly documented and many are subject to conjecture and estimation. The largest living bird, a member of the Struthioniformes, is the common ostrich ("Struthio camelus"), from the plains of Africa and Arabia. A large male ostrich can reach a height of and weigh over . A mass of has been cited for the common ostrich but no wild ostriches of this weight have been verified. Eggs laid by the ostrich can weigh and are the largest eggs in the world today. The largest bird in the fossil record may be the extinct elephant birds ("Aepyornis") of Madagascar, which
Largest prehistoric animals "Argentavis magnificens" which a wingspan of , and a body weight of . The largest-known waterfowl of all time belonged to the Dromornithidae (e.g. "Dromornis stirtoni"). The largest-known of Ciconiiformes was "Leptoptilos robustus", standing tall and weighing an estimated . The largest-known of the hesperornithines was "Canadaga arctica" at long. The largest-known diatryma was "Gastornis" tall, with large individuals up to tall. The largest-known teratorn and the largest flying bird ever was "Argentavis". The immense bird had a wingspan estimated up to and a weight up to . It was as high as an adult human when standing. The largest-known-ever