New York City ? A fossil found in Wyoming has apparently resolved a long-standing question about when bats gained their radar-like ability to navigate and locate airborne insects at night. The answer: after they started flying.

The discovery revealed the most primitive bat known, from a previously unrecognized species that lived about 52 million years ago.

Its skeleton shows it could fly, but that it lacked a series of bony features associated with “echolocation,” the ability to emit high-pitched sounds and then hear them bounce back from objects and prey, researchers said.

Until now, all the early known fossil bats showed evidence of both flying and echolocating, so they couldn’t reveal which ability came first, said researcher Nancy Simmons.