The bony-toothed birds were the largest flying creatures to ever grace our planet's skies.

Nature · Published 3 October 2026 Swipe more like this →

In short: For 50 million years, the Pelagornithidae dominated the world's oceans with wingspans reaching up to six meters. These prehistoric giants, known for their unique, tooth-like beak projections, thrived until the Pliocene-Pleistocene boundary, narrowly missing an encounter with early humans by a mere blink of evolutionary time.

The Pelagornithidae, or pseudotooth birds, were defined by their immense size and specialized anatomy. Their most striking feature was a series of tooth-like bony outgrowths along the edges of their beaks, which were not true teeth but extensions of the premaxillary and mandibular bones. These structures, likely covered by a rhamphotheca in life, were hollow or cancellous, suggesting they were not resilient enough for tearing flesh. Instead, these birds likely used them to grasp soft-bodied prey like cephalopods and fish from the ocean surface while in flight or swimming.

To achieve their massive wingspans—estimated at 5 to 6 meters for the largest species—these birds relied on extreme skeletal pneumatization. Their bones were thin-walled and filled with air sac extensions, allowing them to maintain large sizes while keeping wing loading low. Anatomical evidence, such as the elongated diagonal shape of the humerus and well-developed muscle attachments, indicates they were masters of dynamic soaring. They were likely unable to perform the typical flapping flight seen in modern birds, instead utilizing ocean currents and atmospheric circulation to traverse the open seas.

The evolutionary history of the Pelagornithidae spans from the Early Paleocene to the Pliocene-Pleistocene boundary. While their extinction remains debated, it was likely not caused by direct competition with cetaceans or pinnipeds, which occupied different ecological niches. Instead, a combination of significant ecological shifts, including the beginning of the ice age, plate tectonic changes, and the reorganization of the marine trophic web, likely led to their demise. By the time they vanished, they had reigned as the dominant seabirds of the Cenozoic, leaving behind a fossil record that reveals a complex, highly specialized lineage that remains a subject of intense scientific study.

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