title: Nonecholocating fruit bats produce biosonar clicks with their wings.
abstract: Because evolution mostly acts over millions of years, the intermediate steps leading to a functional sensory system remain enigmatic. Accordingly, there is an ongoing debate regarding the evolution of bat echolocation. In search of the origin of bat echolocation, we studied how Old World fruit bats, which have always been classified as nonecholocating, orient in complete darkness. We found that two of these nonecholocating species used click-like sounds to detect and discriminate objects in complete darkness. However, we discovered that this click-based echo sensing is rudimentary and does not allow these bats to estimate distance accurately as all other echolocating bats can. Moreover, unlike all other echolocating bats, which generate pulses using the larynx or the tongue, these bats generated clicks with their wings. We provide evidence suggesting that all Old World fruit bats can click with their wings. Although this click-based echo sensing used by Old World fruit bats may not represent the ancestral form of current (laryngeal) bat echolocation, we argue that clicking fruit bats could be considered behavioral fossils, opening a window to study the evolution of echolocation.
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel. Electronic address: arjan.boonman@gmx.net.
authors.forename: Arjan
authors.initials: A
authors.lastname: Boonman
authors.affiliation: Department of Biology, Prince of Songkhla University, Songkhla 90112, Thailand.
authors.forename: Sara
authors.initials: S
authors.lastname: Bumrungsri
authors.affiliation: Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel. Electronic address: yossiyovel@hotmail.com.
authors.forename: Yossi
authors.initials: Y
authors.lastname: Yovel
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002685:Chiroptera / Q000502:physiology*; D004455:Echolocation; D010802:Phylogeny; D065854:Spatial Navigation; D014921:Wings, Animal / Q000502:physiology*