Archaeopteryx May Have Launched Into Flight With Powerful Leg Leaps, Study Finds

For more than a century, scientists have debated how Archaeopteryx, a 150-million-year-old feathered dinosaur that combines reptile and bird traits, got off the ground. It had wings that could not lift far above its back and lacked the keeled breastbone modern birds use to power a single-leap launch, leaving the mechanics of its takeoff unresolved. New research led by the University of Southampton, published in Developmental Biology, suggests the answer lay largely in its powerful hind legs.

"Archaeopteryx is the first real bird," said paleobiologist Dr. Neil Gostling of the University of Southampton. "It was covered in feathers and possessed wings, but also retained a number of distinctly dinosaur features, such as a long bony tail, claws on separate fingers, and teeth in a beakless jaw." Because Archaeopteryx could not rely on its wings alone, the researchers, including Professor Markus Heller and Dr. Pauline Provini of the Museum National d'Histoire Naturelle in Paris, examined what its legs could contribute.

The team combined computer modeling, built on earlier observations by the late Dr. Colin Palmer, with measurements from living birds such as gulls, magpies, crows and finches, then adapted the results to Archaeopteryx's anatomy, analyzing forces at the hip, knee and ankle alongside muscle capacity. They concluded that a mid-sized, 400-gram Archaeopteryx could have reached the roughly 7-meter-per-second speed needed for sustained flight after just two or three leaps -- either three bipedal leaps, or two leaps with a downward wing flap between them -- avoiding the more energetically demanding single leap used by many modern birds.

"All birds push with their legs when they take off," said Gostling. "In fact, up to 90 percent of the force required to get off the ground comes from the legs, and then the wings take over." Modern birds such as crows, magpies and seagulls still use the multiple-hop technique, using a single leap only when startled or threatened.