bat map
To assess the route each bat took to return to its roost, the researchers used simulations to measure the echoentropy experienced by the bats along the way. The field where the bats were released was an area of low ecoentropy, so during the first few minutes the bats were flying around, they were looking for more obvious, high entropy landmarks to figure out where they were. It is highly likely that Once it was oriented, it began to fly toward the roost, but not in a straight line. They were a little more meandering, and the group with higher sensory deprivation tended to be more meandering.
The researchers believe this meandering may be due to the bats having trouble maintaining a steady path relying solely on echolocation. It corrected its course when it detected distinctive landmarks, such as certain orchards. By repeating this process, they finally found a place to roost.
But will this be landmark-based navigation, or will it be a simple beacon where the animal picks up something like a distant light and moves towards it?
Researchers argue in favor of cognitive acoustic maps. “If echolocation wasn’t such a restricted sensory modality, I don’t think we would be able to use cognitive acoustic maps to reach conclusions about bats,” Goldstein says. The distance between landmarks that bats used to correct their flight paths was significantly longer than the echolocation sensing range. However, they knew which direction the roost was relative to one landmark, even if the next landmark along the way was not acoustically visible. You can’t do that without mapping the area.
“It would be very interesting to understand how other bats do it in order to make comparisons between species,” Goldstein says. Some bats fly more than 1,000 meters above the ground, so they are unable to use echolocation to detect landmarks. Other species hunt over the ocean, but the team’s simulations show that the ocean is just a huge, low-entropy region. “We’re just getting started, so I’m not only studying navigation, but also behaviors like housing and foraging. I don’t think we know enough about bats in general yet. ” argues Goldstein.
Science, 2024. DOI: 10.1126/science.adn6269
