Study shows early bat can't use sonar as modern one

Scientists found bat fossil of new species dated back to 52.5 million years ago, whose ear structure shows that it would not have been able to employ modern bat's famous sonar, media reported Thursday.

The stuy shows bats learned to fly before they developed their internal "sonar" to navigate and catch insects. The new species found in Wyoming's fossil-rich Green River formation, Onychonycteris finneyi, is the most primitive bat fossil ever found. Onychonycteris had fully developed, flight-capable wings. "This new bat [fossil] is clearly a flying animal, but it lacks the features in the skull that we'd expect to see in an echolocating bat," said Nancy Simmons, chair of Vertebrate Zoology at the American Museum of Natural History in New York and co-author of a new study on the fossil. They also had physical adaptations for echolocation, and a few fossils even have preserved stomach contents that reveal meals of flying insects. "So we know they were flying animals and [were] probably echolocating and catching flying insects," Simmons said. Bats are thought to have evolved from terrestrial mammals, and scientists have long pondered whether they took to the air before or after they could echolocate.