Featured Research

from universities, journals, and other organizations

Bats show ability to instantly change their ear shapes, making their hearing more flexible

Date:
November 14, 2011
Source:
Virginia Tech
Summary:
Within just one tenth of a second, certain bats are able to change the shape of their outer ear from one extreme configuration to another in order to change their hearing, researchers have discovered.

This photo shows a bat with the landmarks on the ear and a high-speed video camera pointed at it in the laboratory of Rolf Müller, Virginia Tech associate professor of mechanical engineering.
Credit: Image courtesy of Virginia Tech

Within just one tenth of a second, certain bats are able to change the shape of their outer ear from one extreme configuration to another in order to change their hearing, researchers have discovered.

"Certain bats can deform the shapes of their ears in a way that changes the animal's ultrasonic hearing pattern. Within just one tenth of a second, these bats are able to change their outer ear shapes from one extreme configuration to another," said Rolf Müller, associate professor of mechanical engineering at Virginia Tech.

Müller and his students wrote a paper on their work that is appearing in Physical Review Letters, a peer-reviewed journal of the American Physical Society. The students are: Li Gao of Shandong, China, a Ph.D. student with Müller, and Sreenath Balakrishnan of Thrissur, Kerala, India, a master's candidate with Virginia Tech's Department of Mechanical Engineering, as well as Weikai He and Zhen Yan, of the School of Physics at Shandong University.

Müller explained the significance of their work, saying, "In about 100 milliseconds, this type of bat can alter his ear shape significantly in ways that would suit different acoustic sensing tasks."

By comparison, "a human blink of an eye takes two to three times as long. As a result of these shape changes, the shape of the animals' spatial hearing sensitivity also undergoes a qualitative change," Müller added.

Bats are flying mammals most well known for their abilities to navigate and pursue their prey in complete darkness. By emitting ultrasonic pulses and listing to the returning echoes, the animals are able to obtain detailed information on their surroundings. Horseshoe bats, in particular, can use their sonar systems to maneuver swiftly through dense vegetation and identify insect prey under difficult conditions.

Acting as biosonar receiving antennas, the ears of bats perform a critical function in bringing about these ultrasonic sensing capabilities.

Using a combination of methods that included high-speed stereo vision and high-resolution tomography, the researchers from Virginia Tech and Shandong University have been able to reconstruct the three-dimensional geometries of the outer ears from live horseshoe bats as they deform in these short time intervals.

Using computer analysis of the deforming shapes, the researchers found that the ultrasonic hearing spotlights associated with the different ear configurations could suit different hearing tasks performed by the animals. Hence, the ear deformation in horseshoe bats could be a substrate for adapting the spatial hearing of the animals on a very short time scale.

The research piggybacks earlier work led by Müller and reported this spring in the Institute of Physics' journal Bioinspiration and Biometrics. That study provided key insights into the various shapes of bat ears among the different species, and illustrated how the differences could affect how their navigation systems worked.

The National Natural Science Foundation of China, Shandong University, the Shandong Taishan Fund, and the China Scholarship Council supported the most recent work.

The collaboration between Shandong University and Virginia Tech started with Müller's opening of a new international laboratory based at the Chinese facility in 2010. The new laboratory focuses on bio-inspired research. In the past, the lab was used by an interdisciplinary group of researchers from the University of Utah, North Carolina State University, and University of California Los Angeles to conduct experiments on the extraordinary capabilities of bats to generate high-powered ultrasonic pulses.

Müller's aspiration in teaching is to bridge the gap between disciplines, especially between biology and engineering.

Müller's research is focused on the understanding of how the most capable biological sensory systems can achieve their best performances. His recent achievements include: providing the first physical explanation for the role of a prominent flap seen in mammalian ears in 2004; discovery of a novel helical scan in the ear directivity of a bat in 2006; discovery of frequency-selective beam-forming by virtue of resonances in noseleaf furrows of a bat, an entirely new bioacoustic paradigm in 2006; establishing the first immediate and quantitative characterization of the spatial information created by a mammal's outer ear in 2007; and now uncovering the acoustic effect of non-rigid ear deformations in bats.


Story Source:

The above story is based on materials provided by Virginia Tech. Note: Materials may be edited for content and length.


Journal Reference:

  1. Li Gao, Sreenath Balakrishnan, Weikai He, Zhen Yan, Rolf Müller. Ear Deformations Give Bats a Physical Mechanism for Fast Adaptation of Ultrasonic Beam Patterns. Physical Review Letters, 2011; 107 (21) DOI: 10.1103/PhysRevLett.107.214301

Cite This Page:

Virginia Tech. "Bats show ability to instantly change their ear shapes, making their hearing more flexible." ScienceDaily. ScienceDaily, 14 November 2011. <www.sciencedaily.com/releases/2011/11/111114133646.htm>.
Virginia Tech. (2011, November 14). Bats show ability to instantly change their ear shapes, making their hearing more flexible. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2011/11/111114133646.htm
Virginia Tech. "Bats show ability to instantly change their ear shapes, making their hearing more flexible." ScienceDaily. www.sciencedaily.com/releases/2011/11/111114133646.htm (accessed August 27, 2014).

Share This




More Plants & Animals News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Super Healthful Fruits and Vegetables: Which Are Best?

Super Healthful Fruits and Vegetables: Which Are Best?

Ivanhoe (Aug. 27, 2014) — We all know that it is important to eat our fruits and vegetables but do you know which ones are the best for you? Video provided by Ivanhoe
Powered by NewsLook.com
Raw: Firefighters Rescue Puppy Stuck in Tire

Raw: Firefighters Rescue Puppy Stuck in Tire

AP (Aug. 26, 2014) — It took Houston firefighters more than an hour to free a puppy who got its head stuck in a tire. (Aug. 26) Video provided by AP
Powered by NewsLook.com
Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Newsy (Aug. 26, 2014) — A study published in the journal "Neurology" interviewed more than 19,000 people and found 15 percent suffer from being "sleep drunk." Video provided by Newsy
Powered by NewsLook.com
Activists Urge NYC Mayor to Ban Carriage Horses

Activists Urge NYC Mayor to Ban Carriage Horses

AP (Aug. 26, 2014) — A group of New Yorkers are putting Mayor Bill de Blasio on notice for what they say is reneging on his campaign promise to ban carriage horses. They rallied Tuesday near the mayor's Gracie Mansion home. (Aug. 26) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins