Perceptual Modalities Guiding Bat Flight in a Native Habitat.

Zhaodan Kong,Shuai Wang,Kayhan Özcimder,Diane Theriault,Nathan Fuller,Erin Gillam,John Baillieul,Margrit Betke

doi:10.1038/srep27252

Abstract

Flying animals accomplish high-speed navigation through fields of obstacles using a suite of sensory modalities that blend spatial memory with input from vision, tactile sensing, and, in the case of most bats and some other animals, echolocation. Although a good deal of previous research has been focused on the role of individual modes of sensing in animal locomotion, our understanding of sensory integration and the interplay among modalities is still meager. To understand how bats integrate sensory input from echolocation, vision, and spatial memory, we conducted an experiment in which bats flying in their natural habitat were challenged over the course of several evening emergences with a novel obstacle placed in their flight path. Our analysis of reconstructed flight data suggests that vision, echolocation, and spatial memory together with the possible exercise of an ability in using predictive navigation are mutually reinforcing aspects of a composite perceptual system that guides flight. Together with the recent development in robotics, our paper points to the possible interpretation that while each stream of sensory information plays an important role in bat navigation, it is the emergent effects of combining modalities that enable bats to fly through complex spaces.

Highlights

Navigation through cluttered environments is a fundamental challenge for animal locomotion[1,2,3,4,5,6]
In order to capture the behavior of free-flying bats in their natural habitat, we conducted a field experiment by observing flight patterns of a colony of Myotis velifer over seven days in an artificial cave habitat located near Johnson City, Texas (Fig. 1)
The probability density functions described for days 2 and 4 in Fig. 4 are clearly bimodal, in contrast to the unimodal PDF of day 1, implying the possibility that not all follower bats are using the same perceptual cues to guide their flight on days when the artificial obstacle was in place

Summary

Introduction

Navigation through cluttered environments is a fundamental challenge for animal locomotion[1,2,3,4,5,6]. Animal navigation requires fusion of spatial memory with information from multiple sensory channels, forming a coherent representation of the environment Bats rely on this composite representation to find their way from roosts to foraging locations that may be some distance away. Our main observations include: (i) the bats were able to adapt to the newly introduced obstacle and develop stereotypical flight patterns within days, demonstrating the development of spatial memory; (ii) some bats reacted to their neighbors before they received the echoes from those bats, indicating the possible role of other sensory modalities (e.g., vision or predictive navigation) to enable agile flight within cluttered spaces and in groups. Our paper is the first instance in which free ranging bat flight behavior around obstacles in their natural habitat has been recorded, detailed, and analyzed in the context of multiple sensory modalities

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Conclusion