Largest organisms were related to the ostrich. They exceeded in height and . The last of the elephant birds became extinct about 300 years ago. Of almost exactly the same upper proportions as the largest elephant birds was "Dromornis stirtoni" of Australia, part of a 26,000-year-old group called mihirungs of the family Dromornithidae. The largest carnivorous bird was "Brontornis", an extinct flightless bird from South America which reached a weight of and a height of about . The tallest carnivorous bird was "Kelenken", which could reach 3 to 3.2 meters in height and 220 to 250 kilograms. The tallest bird ever was
Largest prehistoric animals along with the closely related "Eotriceratops xerinsularis" both with estimated lengths of . Ojoceratops and several other ceratopsians rival them in size. The very largest-known ornithopods, like "Shantungosaurus" were as heavy as medium-sized sauropods at up to , and in length. The largest-known birds of all time might have been the elephant birds of Madagascar. Of almost the same size was the Australian "Dromornis stirtoni". Both were about tall. The elephant birds were up to and "Dromornis stirtoni" was up to in weight. The tallest bird ever was the giant moa ("Dinornis maximus") at tall. The largest-known flight-capable bird was