Biologists and engineers have joined forces to build a new robot bat that’s helping us understand how real bats use echolocation to hunt for food. By creating a robot that can echolocate, the team mimicked a bat’s flight path and explained how bats can quickly determine whether or not their prey is on a leaf. This new bat’s eye view is detailed in a study recently published in the Journal of Experimental Biology

The study was led in part by bat scientist and Smithsonian Tropical Research Institute research associate Inga Geipel. In fact, the robot’s performance largely confirmed Geipel’s hypothesis about real bats. While she expected these results, she still found them gratifying, not so much for herself, but for her furry subjects. 

“I’m always Team Bat,” Geipel tells Popular Science. “They always trick me, they always outsmart me.” 

Echolocation for people in a hurry

Bats use echolocation to find their way and hunt for prey. The winged mammals emit rapid clicking sounds from their mouths and listen for the echoes as those sounds bounce off nearby objects, which could include potential meals. By interpreting the timing and strength of those returning echoes, bats can build a detailed acoustic picture of their surroundings. 

That sonar-based perception process is somewhat akin to the way autonomous vehicles use LiDAR sensors to create a mini map of the world around them. But while self-driving cars rely on dozens of cameras and sensors working in concert, bats accomplish the same task intuitively, with just two ears and a mouth.

Though scientists have long known that bats used echolocation, it was still unclear exactly how they utilize it in the real world, especially in densely packed jungles and rainforests where there are virtually unlimited empty leaves vying for a hungry bat’s attention. 

Entering a bat’s world 

To fly into a bat’s world, the team built on Geipel’s nearly 20 years of research. She says her fascination began when she glimpsed one of the flying mammals deftly fluttering through a lightless night sky. Also a lifelong admirer of music and sound, Geipel was captivated by the notion that these creatures could use those senses to “see” in ways humans can’t comprehend. She hoped her future work would shed some light on that intellectual darkness.

“Seeing the world through sound is a sensory system that is alien to us,” Geipel said. “I find it highly fascinating that bats can fly in total darkness.”

The new robot bat study is something of a spiritual “sequel” to Geipel’s PhD research on bat foraging. That earlier work showed that big-eared bats (Micronycteris microtis) initially approach leaves at a specific angle so that their sonar clicks reflect off smooth forest leaves like an echolocation mirror. Leaves with objects on them, such as  insects, scatter the sonar, resulting in the bat receiving a stronger return pulse. From the bat’s perspective, stronger echoes can mean a tasty lunch.