Oldest bat hunted without sonar

London, Feb 14 (UNI) The most primitive bat found to date lived around 52 million years ago, but did not have the ability to echolocate-- hunting and navigating using sonar-- a unique feature shared by its modern counterparts.

For long, scientists have debated on the issue whether bats learnt to fly first or echolocate first. But, according to new findings published in journal Nature, evidence from the fossils of Onychonycteris finneyi species suggest that bats learnt to fly first and develop the feature of echolocating later to navigate in darkness. The fossil was unearthed in the US state of Wyoming in 2003.

''The three main theories have been that they developed the two abilities together, that flight came first, or that sonar came first. Based on the specimen described in this paper, we were able to determine that this particular animal was not capable of echolocating, which then suggests that bats flew before they developed their echolocation ability,'' said one of the researchers Dr Gregg Gunnell from the University of Michigan.

''It's clearly a bat, but unlike any previously known. In many respects it is a missing link between bats and their non-flying ancestors,'' lead author Dr Nancy Simmons of the American Museum of Natural History said.

Onychonycteris has several surprising features. Crucially, its skull lacks features in and around the ear seen in bats that use echolocation to navigate and hunt.

The primitive bat had claws on all five of its fingers, whereas modern bats have, at most, claws on only two digits of each hand.

The limb proportions are also different from all other bats-- the hind legs are longer and the forearm shorter-- and more similar to those of climbing mammals that hang under branches, such as sloths and gibbons, the Daily Telegraph reported.

It had short, broad wings, which suggest that it probably could not fly as far or as fast as most bats that came after it.

Instead of flapping its wings continuously while flying it may have alternated flapping and gliding while in the air. Onychonycteris's teeth indicate that its diet consisted primarily of insects, just like that of most living bats.

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