Latest Ostrich Theory: ‘Backwards’ Evolution
A scientist has offered long-forgotten German fossils as evidence that ancestors of the ostrich could fly, adding to the debate on the origin of the strange flightless bird.
Peter Houde, an ornithologist at the Smithsonian Institution in Washington who has spent six years tracking down ostrich fossils, said flightless birds such as the ostrich and kiwi probably evolved “backwards” from birds that flew during the age of dinosaurs.
He said his theory is backed by 50-million-year-old fossils of the first known ostriches, uncovered in Germany shortly before World War II and then forgotten. The fossils, he said, indicate that the ancient ostriches were similar to several types of prehistoric birds that could fly.
His theory counters a current belief that flightless birds, called ratites, descended from a single, flightless ancestor before continental drift sent them in different directions on separate land masses.
Both theories could explain how flightless birds evolved on separate continents, a puzzle that has fostered a longstanding controversy in the field of natural history. Adding to the mystery is the fact that ratites have primitive bone structures similar to dinosaurs and reptilian-like jaws.
Houde said there is no fossil evidence that ostriches existed before continental drift split the continents 65 million years ago. He believes the birds evolved about 10 million years later from one or more ancestors that flew across oceans to the separated continents.
“This is very, very hot,” explained ornithologist Stuart Keith of the American Museum of Natural History in commenting on Houde’s research, published in the British science journal Nature.
Houde said the very first birds probably evolved from small dinosaurs and that the ratites evolved “backwards” into flightless creatures, an anachronism from a prehistoric age. “We don’t know how or why this happened, only that it appears to have been the case,” he said.
Houde said ratites may have lost their ability to fly because they had few enemies and no longer needed to expend the massive amounts of energy needed for flight.
The fossils he examined in East Germany two years ago were of three early ostriches, about the size of cranes but with the “same shaggy feathers and reptile jaw” of modern ostriches, the largest and most powerful birds in the world. “They probably got so big because they needed to defend themselves on the plains,” he said. “An adult ostrich can kill a lion cub.”