Was this the biggest bird ever to grace the skies? With a wingspan of about 6.4 metres, Pelagornis sandersi was nearly twice the width of a wandering albatross, the living bird with the greatest wingspan, at 3.5 metres.

Its size puts it on a par with the similarly whopping Argentavis, which was estimated to have a wingspan of 7 metres but may have been smaller than that. Either way, they were all dwarfed by the extinct flying reptile Quetzalcoatlus northropi, perhaps the largest pterosaur, with a wingspan of up to 11 metres.

P. sandersi lived about 25 million years ago. The first fossils – a skull plus some wing and leg bones – were found in Charleston, South Carolina, in 1983. Now Daniel Ksepka of North Carolina State University in Raleigh has formally described it, and worked out its size and how it flew. He estimates its wingspan may have been as much as 7.4 metres.

The bird’s longer wings would have reduced the size of wingtip vortices, which otherwise produce drag. As a result, Ksepka says, P. sandersi was probably a consummate glider that soared for miles over the open ocean with barely a flap of its wings, swooping down now and then to pluck fish or squid from the water.


Getting aloft in the first place may have been another matter altogether, given P. sandersi‘s tiny legs. It probably took off by running down slopes into headwinds, says Ksepka.

Journal reference: PNAS, DOI: 10.1073/pnas.1320297111