Bats Follow Most Efficient Flight Path To Target Multiple Prey

Instead of foraging randomly for food, bats in fact select the most optimal flight route to capture two targets at once.

AsianScientist (Apr. 13, 2016) – Think of the great hunters of the animal world, and the mighty eagle or the majestic tiger probably come to mind. Surprisingly, the diminutive bat also deserves a mention here.

Researchers in Japan have found that when the pint-sized creatures hunt for prey, there’s a method to the madness—bats use “future-target information” to determine the most efficient flight path to capture multiple targets at once. The study, published in the Proceedings of the National Academy of Sciences, is an example of how an animal can dynamically and rationally control its sensing and navigation when hunting.

“Aerial-feeding bats expend a large amount of energy during foraging efforts. However, it has never been revealed what strategy or technique the bats used to repeatedly capture a lot of prey,” study lead and corresponding author, Dr. Emyo Fujioka from the Organization for Research Initiatives and Development, Doshisha University, told Asian Scientist Magazine.

Thus, in the present study, the researchers attempted to quantify the visual and acoustic attention of echolocating bats.

The research team employed experimental and mathematical methodologies to study wild echolocating bats hunting airborne insects in a field surrounded by microphones. They observed almost 800 attacks on prey by approximately 130 bats over six recording days. Of these, 70 attacks in 35 flight paths were selected for analysis.

Differences in arrival time and sound pressure between the microphones allowed the researchers to reconstruct flight paths in 3D and the directions in which bats were emitting sonar beams. The researchers also developed a mathematical model to evaluate the potential flight paths and decision-making of a bat as it hunts two prey items.

Their microphone-array measurements revealed that bats use information about the next target down the line to adjust their flight path; in particular, to maximize short flight times. They direct sonar attention not only to the immediate prey they are targeting, but also to the next one in their path—they will send pulses towards the next prey while still approaching the first.

Accordingly, numerical simulations revealed a possibility that bats shift their flight attention to control suitable flight paths for consecutive capture. This means that bats will take a path in the direction of the next prey just before capturing the immediate prey, so that they can acoustically ‘view’ both prey items. This is crucial, as when a bat only aims its flight direction toward its immediate prey, it rarely succeeds in capturing the next one.

Their findings indicate that bats do not swoop down on insects in a hit-or-miss fashion; rather, they produce dynamic, calculated sonar and flight patterns, and choose the most optimal path for a successful hunt.

“This might be an effective foraging technique used by aerial-feeding bats,” said Fujioka. “These findings might lead to future developments in the research field of selective attention and path planning.”



The article can be found at: Fujioka et al. (2016) Echolocating Bats Use Future-Target Information for Optimal Foraging.

———

Copyright: Asian Scientist Magazine; Photo: Wil/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Coming from a design background, Filzah brings a fresh perspective to science communications. She is particularly interested in healthcare and technology.

Related Stories from Asian Scientist