Fruit bats can transform echoes into images

June 26, 2019

Bats are creatures of the night and are accustomed to complete darkness. They harness their hypersensitive hearing to feed, to fend off prey and to mate.

But that's not the entire story. A new Tel Aviv University study finds that fruit bats actually integrate vision and echolocation to flourish in the dead of night. The new research was led by Prof. Yossi Yovel and conducted by Dr. Sasha Danilovich, both of TAU's George S. Wise Faculty of Life Sciences, and was published on June 26 in Science Advances.

The study focuses on several aspects of fruit bats' integrated vision-echolocation abilities. Bats translate an echo into a visual image and then use their vision to find their way out of a maze and determine the shapes of objects.

"Contrary to popular belief, bats do indeed see, and many of them do use their eyes as much as they use echolocation," Dr. Danilovich says. "But how they integrate vision and echolocation is poorly understood. Our new findings shed light on how fruit bats really operate in darkness."

"How animals -- including humans -- integrate information from different sensory modalities is a major question that still puzzles scientists," Prof. Yovel explains. "Imagine, for example, that you see a car coming from the right, but you hear another one coming from the left. How will your brain process and integrate this information?

"Bats are useful models for studying this and other related phenomena because of their dual reliance on two remote sensory systems: vision and echolocation."

Over several months, the scientists trained the bats hoping to test the extent of their echolocation and vision skills. "These experiments take months, because the bats have to first understand what it is we want of them," says Dr. Danilovich.

In one experiment, the researchers trained the model bats to land on one of two objects in complete darkness for a reward. They also trained them to distinguish between a smooth object and an object perforated with holes.

The team first conducted the experiments under the cloak of darkness and then turned on the lights, eliminating echolocation.

"We found that their brains actually transformed echoes into visual images," Dr. Danilovich says. "It was amazing to see them harness their aural experience and translate it into useful visual data."

The researchers also demonstrated that fruit bats predominantly use vision to find their way out of a maze and to learn the shape of an object.

"When we afforded them the opportunity to attempt to distinguish between a triangle and a cylinder, they only used their vision," Prof. Yovel notes. "When they were tested in total darkness, they were unable to perform the task.

"We have shown that bats are able to translate the acoustic echoes of some objects into visual representations," Prof. Yovel concludes. "We next hope to harness this new echo-to-image paradigm to examine whether bats can build a 3D representation of the world based on echoes alone."
-end-
American Friends of Tel Aviv University supports Israel's most influential, comprehensive and sought-after center of higher learning, Tel Aviv University (TAU). TAU is recognized and celebrated internationally for creating an innovative, entrepreneurial culture on campus that generates inventions, startups and economic development in Israel. TAU is ranked ninth in the world, and first in Israel, for producing start-up founders of billion-dollar companies, an achievement that surpassed several Ivy League universities. To date, 2,500 US patents have been filed by Tel Aviv University researchers -- ranking TAU #1 in Israel, #10 outside of the US and #66 in the world.

American Friends of Tel Aviv University

Related Bats Articles from Brightsurf:

These masked singers are bats
Bats wear face masks, too. Bat researchers got lucky, observing wrinkle-faced bats in a lek, and copulating, for the first time.

Why do bats fly into walls?
Bats sometimes collide with large walls even though they detect these walls with their sonar system.

Vampire bats social distance when they get sick
A new paper in Behavioral Ecology finds that wild vampire bats that are sick spend less time near others from their community, which slows how quickly a disease will spread.

Why doesn't Ebola cause disease in bats, as it does in people?
A new study by researchers from The University of Texas Medical Branch at Galveston uncovered new information on why the Ebola virus can live within bats without causing them harm, while the same virus wreaks deadly havoc to people.

The genetic basis of bats' superpowers revealed
First six reference-quality bat genomes released and analysed

Bats offer clues to treating COVID-19
Bats carry many viruses, including COVID-19, without becoming ill. Biologists at the University of Rochester are studying the immune system of bats to find potential ways to ''mimic'' that system in humans.

A new social role for echolocation in bats that hunt together
To find prey in the dark, bats use echolocation. Some species, like Molossus molossus, may also search within hearing distance of their echolocating group members, sharing information about where food patches are located.

Coronaviruses and bats have been evolving together for millions of years
Scientists compared the different kinds of coronaviruses living in 36 bat species from the western Indian Ocean and nearby areas of Africa.

Bats depend on conspecifics when hunting above farmland
Common noctules -- one of the largest bat species native to Germany -- are searching for their fellows during their hunt for insects above farmland.

Tiny insects become 'visible' to bats when they swarm
Small insects that would normally be undetectable to bats using echolocation suddenly become detectable when they occur in large swarms.

Read More: Bats News and Bats Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.