Synopsis: Jiggles that Help Bat Biosonar

The directional sensitivity of bat biosonar is improved by the wiggling of structures on the bat’s nose and ears.

Bats use ultrasonic signals to navigate in total darkness or track down tiny prey like mosquitoes. To echolocate, they emit ultrasound calls and listen for echoes of those calls as they bounce off objects in the environment. Researchers know that the morphology of a bat’s nose and ears may help it to aim its calls and detect the direction from which the echoes originate, but they don't fully understand what makes bat biosonar so accurate. Now, Rolf Müller of Virginia Tech and colleagues have demonstrated that fast jiggling movements of tissue structures on the nose and in the ears of horseshoe bats dramatically boost their ability to pinpoint the source of incoming signals. The results could guide the design of new bioinspired sensors that may give drones location skills as remarkable as those naturally available to bats.

Using computer models and 3D-printed robots, the team quantitatively analyzed how the directional information that bats derive from echoes of their calls is affected by changes in the shape of their noseleaves—skin and cartilage folds surrounding the bat’s nostrils—and of the outer parts of their ears. Specifically, in horseshoe bats, the noseleaves oscillate between an extended and a contracted conformation and the ears between an upright shape and a bent one. Through numerical simulations and experiments with the robots, the authors compared the number of directions that could be distinguished when these structures were static and when they underwent shape changes. They found an increase in the number of resolvable directions by up to 2–3 orders of magnitude when the noseleaves and ears could deform, compared to when they couldn't.

This research is published in Physical Review Letters.

–Matteo Rini

Matteo Rini is the Deputy Editor of Physics.


More Features »


More Announcements »

Subject Areas

Biological PhysicsAcoustics

Previous Synopsis

Topological Insulators

The Square Root to Topological States

Read More »

Next Synopsis

Related Articles

Finding a “Functional” Cure for HIV
Biological Physics

Finding a “Functional” Cure for HIV

A mathematical model could allow researchers to predict if and when the HIV virus will rebound after antiretroviral therapies stop. Read More »

Focus: Explaining the Ruffles of Lotus Leaves
Biological Physics

Focus: Explaining the Ruffles of Lotus Leaves

A new theory accurately predicts a wide range of leaf shapes and explains the differences between dry lotus leaves and those that grow on water. Read More »

Synopsis: Age Determines How a Human Aorta Stretches
Biological Physics

Synopsis: Age Determines How a Human Aorta Stretches

Younger aortas can expand 5 times more than older ones as fluid pumps through them, a finding that could help to design more successful aortic prostheses. Read More »

More Articles