Editing Megabat (section)

====Echolocation====
Megabats are the only family of bats incapable of [[larynx|laryngeal]] echolocation. It is unclear whether the common ancestor of all bats was capable of echolocation, and thus echolocation was lost in the megabat lineage, or multiple bat lineages independently evolved the ability to echolocate (the superfamily [[Rhinolophoidea]] and the suborder [[Yangochiroptera]]). This unknown element of bat evolution has been called a "grand challenge in biology".<ref>{{cite book | vauthors = Teeling EC, Jones G, Rossiter SJ |chapter=Phylogeny, Genes, and Hearing: Implications for the Evolution of Echolocation in Bats |date=2016 |pages=25–54 | veditors = Fenton MB, Grinnell AD, Popper AN, Fay RN |series=Springer Handbook of Auditory Research |publisher=Springer | location = New York |doi=10.1007/978-1-4939-3527-7_2 |isbn=9781493935277 |title=Bat Bioacoustics |volume=54 }}</ref> A 2017 study of bat [[ontogeny]] (embryonic development) found evidence that megabat embryos at first have large, developed [[cochlea]] similar to echolocating microbats, though at birth they have small cochlea similar to non-echolocating mammals. This evidence supports that laryngeal echolocation evolved once among bats, and was lost in pteropodids, rather than evolving twice independently.<ref>{{cite journal|doi=10.1038/s41559-016-0021|pmid=28812602|title=Prenatal development supports a single origin of laryngeal echolocation in bats|journal=Nature Ecology & Evolution|volume=1|issue=2|pages=21|year=2017|last1=Wang|first1=Zhe|last2=Zhu|first2=Tengteng|last3=Xue|first3=Huiling|last4=Fang|first4=Na|last5=Zhang|first5=Junpeng|last6=Zhang|first6=Libiao|last7=Pang|first7=Jian|last8=Teeling|first8=Emma C.|last9=Zhang|first9=Shuyi|s2cid=29068452}}</ref> Megabats in the genus ''Rousettus'' are capable of primitive echolocation through clicking their tongues.<ref>{{cite journal | last1= Holland| first1= R. A.| last2= Waters| first2= D. A.| last3= Rayner| first3= J. M.| title = Echolocation signal structure in the Megachiropteran bat Rousettus aegyptiacus Geoffroy 1810 | journal = [[The Journal of Experimental Biology]] | volume = 207 | issue = Pt 25 | pages = 4361–4369 | date = December 2004 | pmid = 15557022 | doi = 10.1242/jeb.01288 | bibcode= 2004JExpB.207.4361H| s2cid= 2715542}}</ref> Some species&mdash;the [[cave nectar bat]] (''Eonycteris spelaea''), [[lesser short-nosed fruit bat]] (''Cynopterus brachyotis''), and the [[long-tongued fruit bat]] (''Macroglossus sobrinus'')&mdash;have been shown to create clicks similar to those of echolocating bats using their wings.<ref name=Boonman2014>{{cite journal | last1 = Boonman| first1= A.| last2= Bumrungsri| first2= S.| last3= Yovel| first3= Y. | title = Nonecholocating fruit bats produce biosonar clicks with their wings | journal = Current Biology | volume = 24 | issue = 24 | pages = 2962–2967 | date = December 2014 | pmid = 25484290 | doi = 10.1016/j.cub.2014.10.077 | s2cid= 17789233| doi-access = free | bibcode= 2014CBio...24.2962B}}</ref>

Both echolocation and [[Bat flight|flight]] are energetically expensive processes separately, although no increase in flight energy expenditure was found for two species of echolocating bats compared with other bats and birds .<ref>{{cite journal | last1= Speakman| first1= J. R.| last2= Racey| first2= P. A. | title = No cost of echolocation for bats in flight | journal = Nature | volume = 350 | issue = 6317 | pages = 421–423 | date = April 1991 | pmid = 2011191 | doi = 10.1038/350421a0 | bibcode = 1991Natur.350..421S | s2cid= 4314715}}</ref> Echolocating bats couple sound production with the mechanisms engaged for flight, allowing them to reduce the additional energy burden of echolocation. Instead of pressurizing a bolus of air for the production of sound, laryngeally echolocating bats likely use the force of the downbeat of their wings to pressurize the air, cutting energetic costs by synchronizing wingbeats and echolocation.<ref>{{cite journal | last1=  Lancaster| first1= W. C.| last2= Henson| first2= O. W.| last3= Keating| first3= A. W. | title = Respiratory muscle activity in relation to vocalization in flying bats | journal = The Journal of Experimental Biology | volume = 198 | issue = Pt 1 | pages = 175–191 | date = January 1995 | doi= 10.1242/jeb.198.1.175| pmid = 7891034| bibcode= 1995JExpB.198..175L|url=http://jeb.biologists.org/content/jexbio/198/1/175.full.pdf }}</ref> The loss of echolocation (or conversely, the lack of its evolution) may be due to the uncoupling of flight and echolocation in megabats.<ref name="Book" /> The larger average body size of megabats compared to echolocating bats<ref name="Hutcheon 2004" /> suggests a larger body size disrupts the flight-echolocation coupling and made echolocation too energetically expensive to be conserved in megabats.<ref name="Book">{{cite book |last=Altringham |first=J. D. | name-list-style = vanc |year=2011 |chapter=Echolocation and other senses| title=Bats: From Evolution to Conservation|location=New York |publisher=[[Oxford University Press]] |isbn=9780199207114 }}</ref>