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Mystery of Bat with Extreme Nose Solved

For 60 years scientists did not know why the adult Bourret’s horseshoe bat (Rhinolophus paradoxolophus, the bat on the right in the picture below) has a nose so much larger than the nose of a typical horseshoe bat species (left).

Now Rolf Mueller, an associate professor with the Virginia Tech mechanical engineering department and director for the Bio-inspired Technology (BIT) Laboratory in Danville, Virginia, thinks he has an explanation: The bat uses its elongated nose to create a highly focused sonar beam.


Photos by Rolf Mueller

“Much like a flashlight with an adjuster that can create an intense but small beam of light, the bat’s nose can create a small but intense sonar beam,” Virginia Tech said in a statement released with these photos.

“Mueller and his team used computer animation to compare varying sizes of bat noses, from small noses on other bats to the large nose of the paradoxolophus bat.

Perfect Mark of Evolution

“In what Mueller calls a perfect mark of evolution, he says his computer modeling shows the length of the paradoxolophus bat’s nose stops at the exact point the sonar beam’s focal point would become ineffective.”

Bourret’s horseshoe bat, from the remote rainforests of South East Asia, emits ultrasonic beams, or sonar, from its nose. The echoes of the sound wave convey a wealth of information on objects in the bat’s environment.

The findings with the paradoxolophus bat are part of a larger study of approximately 120 different bat species and how they use sonar to perceive their environment. Set to finish in February 2010, it is hoped the study’s focus on wave-based sensing and communication in bats will help spur groundwork for innovations in cell phone and satellite communications, as well as naval surveillance technology.