A spread-eagled skeleton of a vampire bat is on display in the Smithsonian’s oldest exhibit in the National Museum of Natural History, “but, by today’s standards, it is a bit boring,” said Rolf Mueller, an associate professor of mechanical engineering at Virginia Tech.

Mueller is out to change that. The Smithsonian has updated the osteology hall — known as the Hall of Bones — with augmented reality experiences and modern content.

Through the mobile app "Skin & Bones," soon to be available for iPads and iPhones, a 3-D digital vampire bat skeleton created by a Virginia Tech student team led by Dane Webster, an associate professor in the School of Visual Arts, and Mueller will descend from the actual skeleton and run away as only vampire bats can.

A visitor to the exhibit can select and watch a video interview with Mueller discussing the trials and successes of his fieldwork and hear firsthand what it is like to see the world at the end of a day as a world very much inhabited by bats.

In the wild, Mueller said looking for bats takes planning, such as looking for geographic formations and caves. “But in the end it is asking local people and being lucky.”

"This use of the Smithsonian’s collections is a great example of how digitization opens the door for both research and public education, and it shows how researchers and educators can work together to unlock the potential uses of the digital collections for deeper public engagement," said Deron Burba, the Smithsonian's chief information officer.

Using a vampire bat specimen from the Smithsonian, Mueller has created layers of images using very high-resolution micro CT scans.

Meanwhile, another video on bat echolocation emphasizes the exquisite sensory capabilities of bats by comparing bat sonar with man-made sonar. Engineers worldwide have bat-sense envy.

“A submarine can be about 23 feet wide and has hundreds of sonar emitting and receiving elements distributed over its cross-section, whereas a vampire bat has just a single nose and two ears, each less than an inch long,” Mueller said. “But the ‘noseleaves’ and ears of bats are much smarter than the elements of a technical sonar array. Somehow this smartness can easily compensate for the vast differences in size and numbers.”

Vampire bats belong to a large group called leaf-nosed bats because they emit sound from their nostrils rather than their mouths, and they have a megaphone structure around their nostrils to enhance and direct sound.

“Fleshy appendages around the nostrils act like a megaphone and the two ears act as microphones for sound reception,” said Mueller.

Users can play a game of echolocation through the mobile app by listening to echoes of a bat as sound bounces off different objects. Once they hear four different echoes, users are challenged to identify the object from a mystery echo. Objects include simple shapes, such as a ball, and natural surfaces, such as foliage and rock.

“Bat biosonar is one of the most sophisticated sonar systems in existence,” Mueller said. And, yes, that includes manmade sonar systems.”

In the process of exploring dark caves and studying bats, Mueller is shedding light on the ways that nature’s sonars and sensors can inspire new technology — everything from autonomous micro-air vehicles, to autonomous underwater vehicles, and even land robots.

Some of the bats Mueller has studied have as many as 20 muscles on each ear, whereas humans have just four.

On such bats, both ends of each muscle are connected to the ear which makes it easy for them to change the shape of their ears faster than a human blink of an eye. Only about 15 percent of humans can even wiggle their ears at all. In a bat’s sonar system the ears receive sound and create a complex map of their surroundings.

Anupam Kumar Gupta of Hathras, India, a Ph.D. student in mechanical engineering; and Webster prepared an animation of the dynamic behavior of bat noseleaves for the 166th meeting of the Acoustical Society of America in San Francisco in December 2013. The exhibit was awarded the first price in the “gallery of acoustics” competition.

Mueller’s work is supported by the Institute for Critical Technology and Applied Science at Virginia Tech as an emerging technology in the field of bioinspired science and technology.

Written by Emily Kathleen Alberts


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