I would guess it's due to the fact that not all bats live in low light conditions (think: many species of fruit bats that spend their lives in trees). Mammalian evolution takes longer than it does for invertebrates: the time between generations is much longer.
Diana * * * * * * * * * * * * * * * * * * * * * * * * * * * * Diana R. Tomchick Professor University of Texas Southwestern Medical Center Department of Biophysics 5323 Harry Hines Blvd. Rm. ND10.214A Dallas, TX 75390-8816, U.S.A. Email: diana.tomch...@utsouthwestern.edu 214-645-6383 (phone) 214-645-6353 (fax) On Dec 31, 2014, at 3:28 PM, Ken Harrington wrote: > Interesting article and makes me wonder why bats have such good eyesight if > it is not used to capture insects (food). This article seems to show that > bats which use echo-location for finding food use it exclusively and if it is > jammed they do not get the food. > What purpose do the eyes function as? Seeing as bats spend most of their > lives in low light level conditions, are their eyes working in a different > spectrum or frequency range that that used in conditions of white light? Do > they have a spectrum of eyesight that allows navigating narrow spaces in > total darkness? > > Yeah, I know my mind works in strange ways but I have to question why > something such as eyesight (which takes up a large part of the brain to > process) is provided if it is not used for some type of survival technique > such as finding food. > > Ken > > > Life isn't about waiting for the storm to pass - It's about dancing in the > rain. > > Date: Tue, 30 Dec 2014 21:59:35 +0000 > From: dirt...@comcast.net > To: s...@caver.net; Texascavers@texascavers.com; tag-...@hiddenworld.net > Subject: [SWR] It's bat vs. bat in aerial jamming wars > > It's bat vs. bat in aerial jamming wars > > https://www.sciencenews.org/article/its-bat-vs-bat-aerial-jamming-wars?mode=magazine&context=189468&tgt=nr > > It's bat vs. bat in aerial jamming wars > Special wavering call sabotages aim > By Susan Milius > 10:00am, December 19, 2014 > > SONAR WARS Of the 15 known kinds of squeaks and chirps that a Mexican > free-tailed bat makes, one looks like aerial sabotage. > > Magazine issue: Vol. 186 No. 13, December 27, 2014 > > In nighttime flying duels, Mexican free-tailed bats make short, wavering > sirenlike waaoo-waaoo sounds that jam each other’s sonar. > > These “amazing aerial battles” mark the first examples of echolocating > animals routinely sabotaging the sonar signals of their own kind, says Aaron > Corcoran of Wake Forest University in Winston-Salem, N.C. Many bats, like > dolphins, several cave-dwelling birds and some other animals, locate prey and > landscape features by pinging out sounds and listening for echoes. Some prey, > such as tiger moths, detect an incoming attack and make frenzied noises that > can jam bat echolocation, Corcoran and his colleagues showed in 2009 (SN: > 1/31/09, p. 10). And hawkmoths under attack make squeaks with their genitals > in what also may be defensive jamming (SN Online: 7/3/13). But Corcoran > didn’t expect bat-on-bat ultrasonic warfare. > > Mexican free-tailed bats fight sonar wars, jamming each other’s echolocation > signals in competitions to snatch moths out of the night sky. > > Nickolay Hristov > He was studying moths dodging bats in Arizona’s Chiricahua Mountains when his > equipment picked up a feeding buzz high in the night sky. A free-tailed bat > was sending faster and faster echolocation calls to refine the target > position during the final second of an attack. (Bats, the only mammals known > with superfast muscles, can emit more than 150 sounds a second.) Then another > free-tailed bat gave a slip-sliding call. Corcoran, in a grad student frenzy > of seeing his thesis topic as relevant to everything, thought the call would > be a fine way to jam a buzz. “Then I totally told myself that’s impossible — > that’s too good to be true.” > > Five years later he concluded he wasn’t just hearing things. He and William > Conner, also of Wake Forest, report in the Nov. 7 Science that the > up-and-down call can cut capture success by about 70 percent. Using multiple > microphones, he found that one bat jams another, swoops toward the moth and > gets jammed itself. > > Corcoran says that neighborly sabotage could be especially valuable for the > highly sociable Mexican free-taileds (Tadarida brasiliensis). “If you live in > a cave with a million bats,” he says, “you have to go out and find food — and > compete with a million bats.” > > JAMMED SIGNAL Three video clips filmed outdoors at night show Mexican > free-tailed bats (the larger white shapes) hunting tethered insects (smaller > white shapes). The first clip shows a successful midair catch, and the rest > show how jamming calls foil the attempts. Credit: A.J. Corcoran et > al./Science 2014. > > DirtDoc > > _______________________________________________ SWR mailing list > s...@caver.net > http://lists.caver.net/cgi-bin/mailman/listinfo/swr_______________________________________________ > This list is provided free as a courtesy of CAVERNET. Remember when you are > replying to a message, you are replying to ALL on this list. This a default > setting. If you want to reply to the individual sender then click reply, go > delete the name out of the To: field and insert who you want to reply to. Of > course, you have to know the email address of the person you are wanting to > reply to. > _______________________________________________ > SWR mailing list > s...@caver.net > http://lists.caver.net/cgi-bin/mailman/listinfo/swr > _______________________________________________ > This list is provided free as a courtesy of CAVERNET. > Remember when you are replying to a message, you are replying to ALL on this > list. This a default setting. If you want to reply to the individual sender > then click reply, go delete the name out of the To: field and insert who you > want to reply to. Of course, you have to know the email address of the > person you are wanting to reply to. ________________________________ UT Southwestern Medical Center The future of medicine, today. _______________________________________________ Texascavers mailing list | http://texascavers.com Texascavers@texascavers.com | Archives: http://www.mail-archive.com/texascavers@texascavers.com/ http://lists.texascavers.com/listinfo/texascavers
