The findings, published in the latest issue of the journal Science, put bats on a short list of animals that possess rare superfast muscles. The list includes rattlesnakes, which have them in their tails, and certain other species of reptiles, birds and fish.
Songbirds may have the world’s fastest muscles, since a sound-producing organ allows them to modulate volume and pitch at rates up to 250 times per second. Tying possibly with bats on the fastest muscles list might be a fish that uses gas to its advantage.
“One of the champions among fish is the oyster toadfish, found along the U.S. East Coast,” lead author Coen Elemans told Discovery News. “This animal uses superfast muscles to contract its gas bladder about 200 times per second to generate its courtship ‘boatwhistle.'”
Elemans, an assistant professor in the Center for Sound Communication at the University of Southern Denmark, and his colleagues focused their attention this time on bats. They measured sound production in free-flying Daubenton’s bats as the bats closed in on flying insects.
During this high call rate phase, dubbed the “terminal buzz,” bats send out 160 or more calls per second. As part of this echolocation process, the calls produce echoes when they hit nearby objects. Bats then use these echoes to locate and identify prey.
The researchers identified the superfast muscles that help to control tension in the folds and membranes located within a bat’s larynx. All species with these muscles use the speedy muscles for sound production.
“This is because superfast muscles trade-off force and power for speed,” Elemans explained. “Therefore, the bones and tissue they move can only be very light and small. Because of this tradeoff, superfast muscles would not be useful for locomotion. They simply do not generate enough power.”
Co-author John Ratcliffe, also from the University of Southern Denmark, told Discovery News that bats likely evolved the muscles to meet the demands of hunting at night.
“Echolocation has evolved only in those species of mammals and birds that operate in the dark, or under conditions of uncertain lighting, and so better echolocation was probably an easier option that better eyesight,” Ratcliffe said. “On the other hand, improved flight performance may have co-evolved with improvements in the batâ€™s ability to update spatial information through echolocation. That is, complimentary changes in echolocation and powered flight worked together to improve both target tracking and acquisition.”
Ratcliffe believes the superfast muscles that power part of the bat’s echolocation system are present in all bats that take airborne prey while on the wing — more than 70 percent of bat species alive today.
Brock Fenton, a leading expert on bats who is in the Department of Biology at the University of Western Ontario, told Discovery News that the new study is “excellent and imaginative work. (Itâ€™s) an important contribution to our knowledge about the evolution of echolocation in bats.”
Andrew Bass, a professor in the Department of Neurobiology and Behavior at Cornell University, said “This is an exciting new paper that now adds mammals, in this case bats, to the growing list of vertebrates (fish, reptiles and birds) that have adopted superfast muscles for the rapid production of acoustic signals.”
Elemans and his team suspect that superfast muscles operate in other species, such as in small shrews, which have lightning fast finger movements. They might even exist in humans and other animals.
He said, “A major candidate is the type of muscle that moves the eyes in all vertebrates,” he said. “We do not know yet if this is the same muscle type as bat superfast laryngeal muscle.”