Amazing stuff!
Why did they choose such tiny bats to attach a GPS device? "Study with 6-gram light bats"
"... In a new study, researchers placed GPS trackers on tiny pipistrelle bats living in Israel’s Hula Valley and relocated them to various points within a three-kilometer radius. Some of the animals were also blindfolded or had their sense of smell blocked. Surprisingly, even when forced to rely on echolocation alone, 95% of bats were able to find their way back to their roosts within minutes. The findings suggest that this ability allows bats to create complex mental “maps” of their surroundings, complete with various types of acoustic “landmarks,” which they use to navigate across long distances.
The researchers were also surprised to discover that, when possible, the bats used their vision to enhance navigation. ... even with such small eyes, they can rely on vision under these conditions.” ..."
"... In addition to the field experiments, the team created a detailed map of the entire valley. “We wanted to visualize what each bat experienced during flight and understand how they used acoustic information to navigate,” ...
The model revealed that bats tend to fly near environmental features with higher ‘echoic entropy'—areas that provide richer acoustic information. “During the localization phase, bats conduct a meandering flight that, at a certain point, changes to a directional flight toward their destination, suggesting they already know where they are ..."
From the editor's summary and abstract:
"Editor’s summary
Insectivorous bats are well known to use echolocation to catch prey and navigate around obstacles. It has also been shown that more visually guided fruit bats have spatial cognitive maps of their environment. Goldshtein et al. placed minuscule GPS trackers on tiny pipistrelle bats in conjunction with temporary blocks of vision and olfaction. The authors found that the bats could still navigate across kilometer scales using only echolocation. Thus, echolocation may not only allow for local navigation, but might also translate into an acoustic cognitive map of the environment that the animals can use to navigate over long distances. —Sacha Vignieri
Abstract
Bats are known for their ability to use echolocation for obstacle avoidance and orientation. However, the extent to which bats utilize their highly local and directional echolocation for kilometer-scale navigation is unknown. In this study, we translocated wild Kuhl’s pipistrelle bats and tracked their homing abilities while manipulating their visual, magnetic, and olfactory sensing and accurately tracked them using a new reverse GPS system. We show that bats can identify their location after translocation and conduct several-kilometer map-based navigation using solely echolocation. This proposition was further supported by a large-scale echolocation model disclosing how bats use environmental acoustic information to perform acoustic cognitive map–based navigation. We also demonstrate that navigation is improved when using both echolocation and vision."
Bats use an acoustic cognitive map for navigation (original news release)
Echolocating bats use an acoustic cognitive map for navigation (no public access)
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