Bats have great memories and are able to remember important locations such as their roosts and the best places to find food. Until recently, it was unknown how they manage to recognize and remember these places by echolocation alone. A new study just published in the journal eLife provides a possible explanation.
Bats emit cries and then listen for the echoes in a process called echolocation. This allows them to navigate their dark environment. While bats are not actually blind (despite the phrase “blind as a bat”), echolocation is more efficient and allows them to find small prey items, such as mosquitoes and moths. However, it’s been unclear how bats form mental maps. They rely exclusively on soundwaves, which don’t provide much information, yet the bats can still remember locations easily. The researchers believed that they might be using template based place recognition, a strategy that would allow the bats to remember places based on their echo signatures.
The team built an artificial bat with special microphones and speakers. The device could mimic a bat’s use of echolocation. The team gathered data on echoes at different locations, collecting measurements at normal flight altitudes for bats. The information was then processed by a computer utilizing machine-learning technology. The researchers wanted to see if the computer could “learn” locations based on their echo signatures.
The research team found that template based place recognition was a viable strategy for remembering locations. The computer was able to learn and recall places based on their unique echo signatures. No other information was required, showing that bats can navigate and recall places successfully using just echolocation.
Bats most likely use echo signatures to navigate and form mental maps of their environment. Rather than remembering specific objects, they remember how a place sounds. The research team wants to further investigate how bat navigation works. They believe that their findings could lead to the development of robots that navigate the same way.
Dieter Vanderelst et al. Place recognition using batlike sonar. eLife (2016).