Aepyornis

Brodkorb (1963) listed four species of Aepyornis as valid: A. hildebrandti, A. gracilis, A. medius and A. maximus. However, Hume and Walters (2012) listed only one species, A. maximus. Most recently, Hansford and Turvey (2018) recognized only A. hildebrandti and A. maximus. However, later DNA studies found that Vorombe titan was indistinguishable from A. maximus, and probably represented large females of the species. Aepyornis and other elephant birds are thought to have dispersed and become flightless and gigantic in situ. More recently, it has been deduced from DNA sequence comparisons that the closest living relatives of elephant birds are the New Zealand kiwis, from which they were estimated to have diverged over 50 million years ago. ==Description==

The species of Aepyornis are amongst the largest birds, with weights of estimated for A. hildebrandti and for A. maximus, making it one of the largest, if not the largest bird to have ever lived,{{cite book ==Ecology==

Examination of brain endocasts has shown that both A. maximus and A. hildebrandti had greatly reduced optic lobes, similar to those of their closest living relatives, the kiwis, and consistent with a similar nocturnal lifestyle. A. maximus had relatively larger olfactory bulbs than A. hildebrandti, suggesting that the former occupied forested habitats where the sense of smell is more useful while the latter occupied open habitats. Elephant birds are suggested to have grown in periodic spurts rather than having continuous growth. A 2022 isotope analysis study suggested that individuals of Aepyornis hildebrandti from central Madagascar were mixed feeders that had a large (~48%) grazing component to its diet, similar to that of the living Rhea americana, while A. maximus was probably a browser. Isotope analysis of eggshells attributed to a population of A. hildebrandti from northern Madagascar suggests that this population were probably browsers rather than mixed feeders. The eggs of Aepyornis are the largest known for any amniote, and have a volume of around 5.6–13 litres, and a length of approximately and a width of . The large size of elephant bird eggs means that they would have required substantial amounts of calcium, which is usually taken from a reservoir in the medullary bone in the femurs of female birds. Possible remnants of this tissue have been described from the femurs of A. maximus., Paris ==Extinction==

The extinction of Aepyornis was likely due to human activity after the arrival of humans on Madagascar. The birds were initially widespread, occurring from the northern to the southern tip of Madagascar. suggesting that the eggs regularly provided meals for entire families. The exact time period when they died out is also not certain; tales of these giant birds may have persisted for centuries in folk memory. There is archaeological evidence of giant elephant bird (A. maximus) from a radiocarbon-dated bone at 1880 +/- 70 BP () with signs of butchering, and on the basis of radiocarbon dating of shells, about 1000 BP (= ). After many years of failed attempts, DNA molecules of Aepyornis eggs were successfully extracted by a group of international researchers and the results were published in 2010 in the Proceedings of the Royal Society B. It has also been suggested that the extinction was a secondary effect of human impact due to transfer of hyperdiseases from human commensals, such as chickens and guineafowl. The bones of these domesticated fowl have been found in subfossil sites on the island (MacPhee and Marx, 1997: 188), such as Ambolisatra (Madagascar), where Mullerornis modestus and A. maximus have been reported. ==See also==