Vision, Not Bigger Brains, Helped Pterosaurs Take Flight

For land-dwelling animals, powered flight opens vast new opportunities — from accessing new food sources to expanded mating options. Yet in vertebrates it has arisen just three times: in bats, in birds, and in pterosaurs. New research suggests that for at least one of those lineages, improved sensory processing — not a larger brain — may have been a key early step.

New CT-Scan Evidence From Ancient Relatives

A team led by Michelle Stocker and Sterling Nesbitt (Virginia Tech) used high-resolution CT scanning to create 3-D reconstructions of cranial cavities from a range of species: lagerpetids (small, flightless relatives thought to be close to pterosaur origins), pterosaurs, non-flying dinosaurs, modern crocodiles, and birds. The results, published in Current Biology, let researchers trace how brain anatomy changed before and after the evolution of powered flight.

"Technology like CT scanning gives us ways to ask and address questions that just weren’t possible for so long," Stocker said in a statement.

The scans revealed that lagerpetids already displayed enlarged optic lobes — brain regions associated with visual processing — similar to what is seen in modern birds. This suggests sharper vision may have been an important adaptation that preceded and possibly facilitated aerial maneuvering in the lineage that gave rise to pterosaurs.

Brains and Flight: A Different Path

Crucially, the team found that pterosaurs themselves did not have the relatively large brains typical of birds. "Interestingly, we found that pterosaurs had relatively small brains, comparable in size to those of non-flying dinosaurs and much smaller than that of birds," Nesbitt said. In other words, successful powered flight in pterosaurs appears to have evolved without the pronounced brain enlargement seen in birds.

These findings highlight that evolution can produce similar capabilities through different combinations of anatomical and neural changes. Enhanced vision and other sensory or motor specializations may have compensated for smaller overall brain size in pterosaurs, allowing agile aerial behavior without the bird-like increase in brain volume.

Why It Matters

This study refines our understanding of how complex behaviors like powered flight evolve. It shows that a specific neural enhancement — improved visual processing — could be a critical first step, and that large brain size is not an obligatory route to mastering three-dimensional aerial locomotion.

Study Source: Michelle Stocker, Sterling Nesbitt et al., Current Biology.