Swimming Proto-Birds?

During the past decade, numerous discoveries have been made that have confirmed the hypothesis that birds evolved from dinosaurs. These fossils have given paleontologists important insight into how adaptations like feathers evolved, but one of the most hotly debated topics in paleobiology is how birds began to fly. Some scientists prefer a "ground up" model in which feathered dinosaurs began jumping into the air, but others think a "trees down" hypothesis (where feathered dinosaurs would have started gliding first) is more plausible. There once was another hypothesis, however, involving bird ancestors that lived along an ancient shoreline.

In 1920, the zoologist Horatio Hackett Newman published his textbook Vertebrate Zoology, and in it he proposed a unique idea for the origin of birds. Newman thought that the reptilian ancestors of birds had the beginnings of feathers in elongated scales, and if these bird ancestors jumped off cliffs to dive after fish, these scales could have aiding them in aiming their strike. If they could flap their arms, so much the better, and so flying birds would have evolved from these divers. Flightless birds like penguins, by contrast, would have evolved from similar reptiles that used their arms to flap underwater.

To bolster his case Newman even supposed that the earliest known bird, Archaeopteryx, was adapted to climbing rocky cliffs at the shore and had teeth adapted for catching fish. He did not have proof for his views, but there did not seem to be much evidence that directly refuted it. At the time he proposed this hypothesis, there were very few fossils to test his ideas.

Unfortunately for Newman, his hypothesis was not well accepted at the time and was soon relegated to the scientific dust bin. New evidence has also failed to throw support to his ideas, but this is not to say that we should ignore what Newman wrote. His hypothesis is important to understanding how scientists form ideas based upon the evidence available. Swimming proto-birds might seem a bit silly to us now, but it is an interesting tidbit of science history.

Riley Black | | READ MORE

Riley Black is a freelance science writer specializing in evolution, paleontology and natural history who blogs regularly for Scientific American.