Blaring a special call at just the right instant ruins another’s sonar-guided swoop
Mexican free-tailed bats make short waaoowaaoo sounds that sabotage each other’s sonar-guided aim in duels over the right to gulp a flying moth out of the night sky.
Tadarida brasiliensis, like other aerial hunting bats, locates its prey by making little calls and listening for any echoes bouncing off a moth. Aaron Corcoran of Wake Forest University in Winston-Salem, N.C., was recording other bat sounds when he picked up the strange wavering sirenlike calls in sequences that suggested that free-taileds might be jamming each other. By standing on a scaffold with a spotlight to watch wild free-tailed bats hunt, and also by playing recorded jamming calls, he found that well-timed calls can foil up to 85.9 percent of attempts to capture a moth. This marks the first example of an echolocating animal routinely jamming its own kind, Corcoran says. He and William Conner, also at Wake Forest, describe the jamming in the Nov. 7 Science.
THWARTED 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. (Video and audio are slowed to one-twentieth of their natural speed.) Credit: A. Corcoran
Bat jamming signals
A.J. Corcoran and W.E. Conner. Bats jamming bats: Food competition through sonar inference. Science. Vol. 346, November 7, 2014, p. 745. doi: 10.1126/science.1259512.
S. Milius. Hawkmoths squeak their genitals at threatening bats. Science News Online, July 3, 2013.
S. Milius. ‘Whispering’ gives bats the drop on prey. Science News. Vol. 178, September 11, 2010, p. 12.
S. Milius. Carlsbad’s 8 million ‘lost’ bats likely never existed. Science News. Vol. 175, February 14, 2009, p.12.
S. Milius. Superloud moth jams bat sonar. Science News. Vol. 175, January 31, 2009, p.10.
A.J. Corcoran, J.R. Barber and W.E. Conner. Tiger moth jams bat sonar. Science. Vol. 325, July 17, 2009, p. 325. doi: 10.1126/science.1174096.