In 1983, in South Carolina, U.S.A., work was under way to expand Charleston International Airport by adding a new terminal. In order for construction to go ahead, a large earth moving operation was required, but upon digging into the rock, a wealth of ancient fossils were discovered. Albert Sanders was curator at the Charleston Museum at the time and led the excavation at the dig site in order to collect and study the prehistoric remains.
25-28 million years ago the world was a different place; the Earth was much warmer and there was less ice at the poles meaning that sea levels were significantly higher. The area where Charleston airport is now situated was once underwater, and the rock that was dug into for the excavation was once the seabed. The fossilised seabed held many interesting remains, including whales and fish, but one volunteer at the site, James Malcom, discovered something that stood out; some assorted bones, including a skull, of what appeared to be a large bird. Sanders, the dig leader, was a whale expert, not a bird expert, so the remains were archived in a drawer at the museum to be analysed later.
Decades later and the airport is busy and thriving, but the prehistoric bird bones lay untouched in a museum archive, that is until Daniel Ksepka, curator of science at the Bruce Museum in Greewich, Connecticut, was invited to analyse the finds. Ksepka is a palaeontologist and expert in ancient bird remains who ended up discovering something rather interesting.
Ksepka used computer simulations to try to piece together the size and shape of the bird and try to model its flight patterns. The bird was always known to be a member of the pelagornithid family (a group of huge sea birds that are characterised by the presence of tooth-like spikes in their beaks) but it was soon realised that this individual was a whole new species and not only was this a new species but it seemed to be the largest bird that ever took to the skies!
An artist’s depiction of Pelagornis sandersi in flight over an ancient ocean. By Liz Bradford.
The bird was named Pelagornis sandersi (named after Sanders, the original excavator); it was a huge animal, boasting a wingspan of up to 7m and it perhaps could have been wider when flight feathers are factored in. Like other birds in the pelagornithid family, it lived most of its time out at sea, catching soft-fleshed marine creatures like fish and invertebrates; we know this because of its ‘teeth’ which are unusual as far as bird beaks are concerned. It had short, stumpy legs meaning that it was awkward on land, but more streamlined when in flight. Ksepka’s computer modelling demonstrated that sandersi’s size and shape made it an extremely effective glider that would have required very few wing beats in order to travel huge distances, instead, it soared through the air riding air currents and thermal up-draughts. Sandersi was also an extremely light bird, given it’s size; based on its bone density, it’s calculated that an individual might have only weighed between 20kg to 40kg (compare that to a modern-day ostrich (Struthio camelus) which weighs in at 100kg), this would have assisted in keeping it aloft.
The largest bird capable of flight that currently exists is the wandering albatross (Diomedea exulans) which boasts a measly wingspan of 3.5m. Although sandersi and the albatross are very different birds in many ways, they share many similarities, most notably their lifestyle; spending almost their entire lives out at sea, soaring above the waves, swooping down to catch fish and other prey and rarely coming to land, except for mating and replacing flight feathers. The albatross is also notable for its struggle to get airborne, a struggle shared by its ancient cousin. Sandersi was so perfectly adapted to its aerial lifestyle that it would have been positively useless on the ground, struggling to move around and protect itself and struggling to take off again. It’s quite possible that sandersi would have been completely incapable of taking flight unless it ran downhill into a good wind, or even leapt from a cliff in favourable conditions.
The Wandering Albatross (Diomedea exulans) is the largest flying bird currently in existence, but larger birds existed in the past. Photo Credits.
Sandersi was the largest bird to ever fly, but other types of animal have also taken to the sky in the past. Bats and insects still live around us, but between 228-66 million years ago, there lived a group of animals called pterosaurs; large flying reptiles that soared in the skies over the dinosaur world. One of these animals, named Quetzalcoatlus, was the largest flying animal to ever live with a mighty wingspan of 15m and when it landed, it stood as tall as a giraffe! Pterosaurs ruled the skies for a very long time before birds evolved and eventually dethroned them, and it was a very long time still before sandersi arrived to take the title of largest flying bird.
Quetzalcoatlus was a gigantic flying reptile that holds the record as the largest animal to ever take flight. Photo Credits.
Before the discovery of sandersi, the record holder was Argentavis magnificens (another seabird which lived around 6 million years ago, much later) but Ksepka reckons that there may be other specimens out there that will break the record. He believes that it’s possible that we may find birds with 10m wingspans, but any more than that is quite unlikely due the physics involved in flight.
Life on Earth has had 3.5 billion years to experiment with many different forms. The animal kingdom is richly varied and full of remarkable and fascinating creatures but some of the most amazing are no longer with us. Over 99% of all species that have ever existed are now extinct, among them are astonishing animals that are almost unimaginable. Who knows what wonderful and bizarre creatures are still waiting to be discovered deep in the ground!