Bat Video Wins National Science Award

See the video

With dramatic video of a Big Brown bat tracking and capturing a praying mantis, researchers at the University of Maryland devised an award-winning way to show how a bat uses its acute acoustic senses to survive.

Using slow-motion video, animation and sound, psychology professor Cynthia Moss and doctoral student Kaushik Ghose put together a visual presentation that won them a top international prize in the 2004 Science and Engineering Visualization Challenge sponsored by the National Science Foundation and Science Magazine.

The competition challenges scientists to find a visual way to depict the findings of their research. The Maryland team won in the non-interactive category.

Bat Sonar
Moss and Ghose study how bats use sound to probe their environment and process information. "You can learn about general principles by studying a specialized animal like the echolocating bat," says Moss, director of the university's Neuroscience and Cognitive Science Program.

"Bats are good model systems for the study of hearing, because it's their primary sense to find food and navigate, sometimes in complete darkness. In fact, bats rely on their ears much like we rely on our eyes."

Bats emit a sound - a chirp that is out of the range of human hearing - that bounces off objects around the bat. The bat hears echoes of those signals and uses them to locate and capture food, navigate in flight and other survival functions.

Seeing How a Bat Hears
To get a better idea of how a bat uses sonar, Ghose designed a unique system of 16 microphones placed around the lab space where the research team's bats fly. The microphones recorded the patterns of the bat's chirps. At the same time, two infrared cameras videotaped the bat as it tracked a praying mantis.

In their visualization, Ghose and Moss put the video side-by-side with computer animation that reconstructs the bat's sonar beam pattern and shows how the bat's movement corresponds to the patterns of sound.

In real time, it took the bat only two seconds to intercept the insect. But Ghose and Moss slowed the video and the audio of the bat's chirps by a factor of 16 to create a 32-second video, with sounds of bat chirps that are audible to humans.

"You can see the details of behavior that you can't observe just by watching in real time," says Ghose, "and you can see how the bat's information is updated over time."

Ears on the Prize
The visualization shows how "the bat tries to keep the loudest part of sound on the target, much like a human would keep an eye trained on an object," says Moss. "You can look at the beam pattern of the bat and see selective sampling.

It also demonstrates that the bat can move in one direction while directing its sonar in a different direction," says Moss, similar to the way a basketball player might look in one direction, but pass the ball to a player in a completely different direction.

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