The extinct genus Pelagornis represents the largest flying bird discovered, with P. sandersi possessing a wingspan that dwarfs any modern avian. Its massive size raises a fundamental question: how did such a creature sustain itself while remaining light enough for flight? The answer lies in the bird’s unique anatomy and a specialized diet drawn from the ancient oceans. Researchers have reconstructed the feeding habits of this giant from the fossil record, revealing a predatory niche unlike any seen today.
Defining the Giant Bird
Pelagornis belongs to the family Pelagornithidae, a group of extinct marine birds commonly referred to as the bony-toothed birds or pseudodontorns. These colossal flyers dominated the oceans throughout the Cenozoic Era, with fossils spanning roughly 62 to 2.5 million years ago. The species P. sandersi had an estimated wingspan reaching up to 24 feet (7.4 meters), making it twice the size of the largest living flying bird, the wandering albatross. Its immense size placed physical constraints on its hunting and feeding capabilities.
The Primary Diet Hypothesis
The consensus among paleontologists is that Pelagornis was a carnivore whose diet consisted almost entirely of soft-bodied marine life. This giant seabird primarily consumed slippery prey such as cephalopods (squid) and small- to medium-sized fish. The preference for this type of prey is derived from the structure of its feeding apparatus, which was designed for rapid grasping rather than powerful crushing. This soft-bodied diet fueled the bird’s energy needs without requiring it to take on large, struggling, or heavily armored prey. The birds swallowed their catches whole, as their jaw structure was not suited for tearing flesh or breaking bones.
Structure of the Jaws and Evidence
The most distinguishing feature of Pelagornis and the strongest evidence for its diet is the presence of prominent “pseudoteeth” lining its jaws. These were not true teeth like those found in mammals or reptiles; instead, they were hollow, bony projections that grew directly from the jawbone, known as tomial serrations. The bony projections were covered in a hard, keratinized sheath, forming a specialized gripping surface. This morphology was perfectly adapted for securing slippery prey like fish and squid that were seized in the water.
Crucially, the hollow nature of these pseudoteeth made them relatively fragile, meaning they would have easily broken if used to crush hard-shelled organisms or bones. This structural limitation acted as a biological constraint, forcing the bird to pursue a soft-bodied diet. The pseudoteeth functioned as a one-way trap, allowing the bird to grab and hold a fish or cephalopod effectively until it could be swallowed.
Hunting Methods and Habitat
The enormous wings of Pelagornis indicate that it was a highly efficient dynamic soarer, a flight technique relying on wind currents and air pockets over the open ocean, similar to modern albatrosses. This strategy allowed the bird to cover vast distances with minimal energy expenditure, perfectly suiting its pelagic lifestyle over deep waters. The hunting method is thought to have been surface-seizing or skimming.
The bird would use its long, tooth-lined beak to snatch prey swimming near the surface of the water without having to land or dive deeply. Its lightweight, delicate bones and immense wingspan would have made deep diving physically impossible. The hunting strategy was likely a graceful, energy-efficient glide followed by a quick snatch of small, easily digestible marine life.