Is it a bird? Is it a plane? Any confusion is not entirely unreasonable.

A newly discovered prehistoric bird was in fact only slightly smaller than a two-seater aeroplane. Pelagornis sandersi had a wingspan of between 6.1 and 7.4m, which makes it the largest flying bird yet discovered.

Pelagornis sandersi also had stumpy legs and a mouth filled with strange, bony spikes, which made it look like a dragon, according to Dan Ksepka, the palaeontologist who pieced together its bones.

“This was a remarkable fossil,” Dr Ksepka said. “Almost like something out of Game of Thrones. There is simply nothing like them around today.”

The bird’s bones were unearthed in 1983, during the expansion of Charleston airport in the US state of South Carolina. It has been named after Albert Sanders, the curator at Charleston Museum who led the original excavation.

The bones then spent almost three decades in a drawer at the museum, until they were rediscovered by Dr Ksepka, then of North Carolina State University.

Not afraid of skeletons in cupboards, Dr Ksepka pieced together the bird’s skull, shoulder blade, leg and wing bones. He then extrapolated its mass, wingspan and wing shape.

These findings were fed into a computer program, which estimated how the bird might have flown. This suggested that, like the modern albatross, the prehistoric bird was an efficient glider, and would barely have needed to flap its wings in order to keep moving. It would probably have reached speeds of up to 37mph (60 km/h).

But the 21.8kg bird would have struggled to take off. It was too heavy, and its feet too small to run on water like a goose or swan. Its mass was too great, meanwhile, for its wing muscles to flap sufficiently to achieve take-off. “I think they just waited on the beach for a strong wind to carry them aloft,” Dr Ksepka said.

Once in flight, the bird would have used the spikes in its beak to spear prey, such as other birds. Such spikes are, in fact, significantly less rare than hens’ teeth: similar “toothed” birds lived between 55 and 3 million years ago.

Pelagornis sandersi is likely to have lived between 25 and 28 million years ago. Other oversized avians include Argentavis magnificens, which lived 6 million years ago and had a wingspan of 5.5 to 7m.

The royal albatross, the largest flying bird alive, has a wingspan of around 3m. A Cessna aeroplane, by contrast, has a wingspan of around 10m.

Questions for debate and discussion

  1. What do scientists know about the Pelagornis sandersi?
  2. What evidence can scientists use to find out about the way extinct species lived?
  3. Explain why this bird may have had trouble walking?
  4. Scientists don’t know why these enormous birds died out. Do you have any ideas?

Relevant resources

Natural History Museum
Find out what schools can do at the museum with this pupil-made video.

Grouping animals and variation
These PowerPoint presentations introduce students to grouping animals, birds, amphibians, reptiles, mammals and fish, and can be used alongside literacy and numeracy topics. 

Aerodynamic albatross
In this video from BBC Nature, you’ll get a close-up look at the way that an albatross flies, and learn some amazing facts about these endangered sea birds.

Fossils factsheet
Use this well-designed sheet full of fun fossil facts to inspire students on a research quest about extinct creatures, fossils or evolution.