Elephant bird

Elephant birds are members of the extinct ratite family Aepyornithidae, made up of large to enormous flightless birds that once lived on the island of Madagascar. They became extinct, perhaps around 1000–1200 CE, probably as a result of human activity. Elephant birds comprised the genera Mullerornis, Vorombe and Aepyornis. While they were in close geographical proximity to the ostrich, their closest living relatives are kiwi, suggesting that ratites did not diversify by vicariance during the breakup of Gondwana but instead evolved from ancestors that dispersed more recently by flying. In September 2018, scientists determined that Vorombe titan reached weights of 730 kg (1,600 lb) and stood 3 m (9.8 ft) tall, making it the world's largest bird, slightly larger than the much older Dromornis stirtoni. Elephant birds have been extinct since at least the 17th century. Étienne de Flacourt, a French governor of Madagascar in the 1640s and 1650s, mentions an ostrich-like bird said to inhabit unpopulated regions, though it is unclear whether he was repeating folk tales passed on from generations earlier. In 1659, Flacourt wrote of the 'vouropatra – a large bird which haunts the Ampatres and lays eggs like the ostriches; so that the people of these places may not take it, it seeks the most lonely places.' Marco Polo also mentioned hearing stories of very large birds during his journey to the East during the late 13th century. These accounts are today believed to describe elephant birds. Between 1830 and 1840 European travelers in Madagascar saw giant eggs and egg shells. English observers were more willing to believe the accounts of giant birds and eggs because they knew of the moa in New Zealand. In 1851 the French Academy of Sciences received three eggs and some bone fragments. In some cases the eggs have a length up to 34 cm (13 in), the largest type of bird egg ever found. The egg weighed about 10 kg (22 lb). The egg volume is about 160 times greater than that of a chicken egg. Aepyornis is believed to have been more than 3 m (9.8 ft) tall and weighed perhaps in the range of 350 to 500 kg (770 to 1,100 lb). In September 2018, scientists reported that Vorombe titan reached weights of 730 kg (1,600 lb), and based on a fragmentary femur, possibly up to 860 kg (1,900 lb), making it the world's largest bird. Only the much older species Dromornis stirtoni from Australia rivals it in size among known fossil birds. In the same report, the upper weight limits for A. maximus and D. stirtoni were revised to 540 and 730 kg, respectively. Four species are usually accepted in the genus Aepyornis today, but the validity of some is disputed, with numerous authors treating them all in just one species, A. maximus. Up to three species are generally included in Mullerornis. Several ratites outside of Madagascar have been posited as 'aepyornithid'-like and could potentially make this clade considerably more speciose. These include Eremopezus from the Eocene of North Africa, unnamed Canary Island remains and several Neogene taxa in Eurasia. Aepyornis maximus is commonly known as the 'elephant bird', a term that apparently originated from Marco Polo's account of the rukh in 1298, although he was apparently referring to an eagle-like bird strong enough to 'seize an elephant with its talons'. Sightings of eggs of elephant birds by sailors (e.g. text on the Fra Mauro map of 1467–69, if not attributable to ostriches) could also have been erroneously attributed to a giant raptor from Madagascar. The legend of the roc could also have originated from sightings of such a giant subfossil eagle related to the African crowned eagle, which has been described in the genus Stephanoaetus from Madagascar, being large enough to carry off large primates; today, lemurs still retain a fear of aerial predators such as these. Another might be the perception of ratites retaining neotenic features and thus being mistaken for enormous chicks of a presumably more massive bird.