Pterosaurs: Predators Of Ancient Skies

Pterosaurs, the mighty winged-lizards, soared ancient skies expertly hunting for prey. Because they evolved from reptiles prior to modern birds, it was once believed that pterosaurs were primitive, passive fliers. They were seen as gliders, rather than skillfull hunters. Being the earliest vertebrates to have evolved powered flight, we now recognize that they were powerful fliers, chasing and catching their prey on the wing.

One clue to this revelation is a small bone at the front of the wing bone which curves back towards the shoulder, roughly like an elongated thumb on a spread hand. Modern birds have a small but vital feather, the aula, in this position. It shifts, acting like the leading edge on some airplane wings, redirecting the airflow over the wing, and allowing major changes in speed and angle in the air for comparatively little effort. It seems clear the pterosaurs’ extended thumb would have held a flap of membrane in a similar position at the front of the wing, and for a similar purpose.

Their skulls hold the other clue; they have much larger brain cases in relation to their size than their earth-bound contemporaries. Co-ordination of flight requires tremendous brainpower, and co-ordination of active flight, with the constant shift in the shape and location of massive wings, even more so. Nature is extremely parsimonious, not frittering away investment in any organ where it is not needed. Given the engineering challenges and the energy costs of getting each additional gram of weight off the ground, pterosaurs would never have developed such large and heavy “on board computers” unless they clearly paid their own way in faster, more nimble flight that would have allowed their owners to catch more prey and outmaneuver competing aerial hunters and scavengers.