The bird species Pelagornis sandersi is one of the largest known flying birds. It also boasts the largest wingspan ever recorded, measuring between 21 and 24 feet. This magnificent creature roamed the planet between 33.9 and 23 million years ago.
The fossil that first introduced Pelagornis sandersi to science was discovered in the early 1980s beneath the international airport in Charleston, South Carolina.
Pelagornis sandersi was so massive that researchers initially debated whether it could even fly. Ultimately, they concluded that it likely glided low over the water’s surface, using a phenomenon known as the “wing-in-ground effect” to gain extra lift.
An Unsolved Mystery
However, researchers still don’t know exactly how this creature fed itself. Some have speculated that while hunting, the toothy giant dipped its beak into the water like the modern skimmer (Rynchops). Skimmers fly low over the water and occasionally submerge about 19 percent of their beak to catch marine prey.
The bizarre pseudoteeth of Pelagornis—spike-like projections on the upper and lower parts of its beak—seemed to support that idea. Researchers suggested those features helped the bird catch prey as it glided over the water’s surface. The arrangement of bones in its jaw and the anatomy of its vertebrae also pointed to that possibility. But new research has seriously challenged the skimming theory.
What Did Scientists Discover?
A team from PSL University in Paris, Lincoln University, and the University of Reading argues that Pelagornis sandersi would have struggled with the energy costs of gliding close to the water’s surface.
The scientists proposed that Pelagornis would face enormous hydrodynamic drag if it tried to dip its beak into the water like skimmers do. They calculated that in that scenario the bird’s air resistance would increase ninefold, making the maneuver too energy-intensive to sustain.
The team confirmed this by modeling the immersion of even a small portion of the beak, such as five percent.
“Our research shows that despite Pelagornis being one of the largest flying birds in history, it could not have covered the enormous energy costs required for catching prey by gliding over the water’s surface,” said co-authors Olivia Hellier-Price, Chris Venditti, and Stuart Humphries in an interview with IFLScience.
They did not completely rule out brief dips, since birds can produce short bursts of power above their sustained output during certain maneuvers. But based on fossil data alone, it’s hard to tell whether Pelagornis could manage even those short, costly actions.
So how did this prehistoric bird catch its prey? It may have stolen food from other birds (kleptoparasitism) or raided nests. Alternatively, Pelagornis could have been a predator that snatched small birds in mid-air and ate them. For now, there is no definitive answer.
The findings were published in the journal Royal Society Open Science.
