Horseshoe bats and Old World leaf-nosed bats have two discrete types of pinna motions

Yin, Xiaoyan; Qiu, Peiwen; Yang, Lili; Müller, Rolf

doi:10.1121/1.4982042

Cited by 14 publications

(15 citation statements)

References 22 publications

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“…biosonar | ear motions | Doppler shifts | time-frequency signatures | nonlinear sensing C onspicuous pinna motions (1)(2)(3)(4)(5) are an integral part of biosonar behaviors in horseshoe bats and Old World leafnosed bats [families Rhinolophidae and Hipposideridae (6,7)]. These motions have been demonstrated to enhance sensing and navigation performance (8-10), but the functional role of these dynamic features and the underlying mechanisms have yet to be fully understood (7).…”

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confidence: 99%

Fast-moving bat ears create informative Doppler shifts

Yin

Müller

2019

Proc. Natl. Acad. Sci. U.S.A.

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Many animals have evolved adept sensory systems that enable dexterous mobility in complex environments. Echolocating bats hunting in dense vegetation represent an extreme case of this, where all necessary information about the environment must pass through a parsimonious channel of pulsed, 1D echo signals. We have investigated whether certain bats (rhinolophids and hipposiderids) actively create Doppler shifts with their pinnae to encode additional sensory information. Our results show that the bats' active pinna motions are a source of Doppler shifts that have all attributes required for a functional relevance: (i) the Doppler shifts produced were several times larger than the reported perception threshold; (ii) the motions of the fastest moving pinna portions were oriented to maximize the Doppler shifts for echoes returning from the emission direction, indicating a possible evolutionary optimization; (iii) pinna motions coincided with echo reception; (iv) Doppler-shifted signals from the fast-moving pinna portion entered the ear canal of a biomimetic pinna model; and (v) the time-frequency Doppler shift signatures were found to encode target direction in an orderly fashion. These results indicate that instead of avoiding or suppressing all self-produced Doppler shifts, rhinolophid and hipposiderid bats actively create Doppler shifts with their own pinnae. These bats could hence make use of a previously unknown nonlinear mechanism for the encoding of sensory information, based on Doppler signatures. Such a mechanism could be a source for the discovery of sensing principles not only in sensory physiology but also in the engineering of sensory systems.biosonar | ear motions | Doppler shifts | time-frequency signatures | nonlinear sensing C onspicuous pinna motions (1-5) are an integral part of biosonar behaviors in horseshoe bats and Old World leafnosed bats [families Rhinolophidae and Hipposideridae (6, 7)]. These motions have been demonstrated to enhance sensing and navigation performance (8-10), but the functional role of these dynamic features and the underlying mechanisms have yet to be fully understood (7). In the acoustic domain, source or receiver motions can result in Doppler shifts, i.e., nonlinear scaling of signals in time and frequency. The possibility of pinna-induced Doppler shifts had been mentioned as an aside in early work by Pye and coworkers (2, 3, 11) but has not been considered further-let alone investigated in any depthin the literature since. This complete neglect is regrettable, because ear-generated Doppler shifts could constitute a previously unknown, nonlinear mechanism for the active encoding of sensory information. To test this hypothesis, we have carried out a quantitative experimental investigation of the hypothesis that pinna motions cause functionally relevant Doppler shifts in bats. For pinna-generated Doppler shifts to have a functional role, five necessary conditions must be met: (i) pinna surface speeds must be high enough to produce Doppler shifts that exceed the animal's per...

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Fast-moving bat ears create informative Doppler shifts

Yin

Müller

2019

Proc. Natl. Acad. Sci. U.S.A.

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“…to alternate between rigid and non rigid motions [107] and have been shown to possess a large range of variability at least in the rigid motions [108]. Hence, it may be hypothesized that this variability provides a substrate for adaptation that would allow the animals to encode more useful sensory information.…”

Section: Discussionmentioning

confidence: 99%

Biomimetic detection of dynamic signatures in foliage echoes

Bhardwaj¹,

Khyam²,

Müller³

2021

Bioinspir. Biomim.

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I would like to thank Dr. Rolf Müller for giving me the opportunity to pursue this research. I appreciate immensely his trust and guidance throughout my time working on this research.His leadership, approach to problem-solving, attention to detail, and seemingly limitless wide-ranging knowledge of science, are the reference points I will always aspire to reach in my career. I would also like to thank my committee members, Dr. Alexander Leonessa and Dr. Michael Roan, for their mentorship and technical advice. I wish to acknowledge Dr.Mohammad Omar Khyam and David Alexandre, who contributed to a significant part of this research. I'd also like to acknowledge Liujun Zhang, for his help in collecting the data for this project, and for his friendship. I'd also like to thank the other grad students in the lab

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“…3), based on the maximum changes in the distances between all five landmark points during the motion. If the maximum change was less than 2 mm, the motion was classified as rigid, else it was classified as non-rigid (Yin et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

“…Numerical and physical methods indicate that noseleaf motions should impact the distribution of the emitted energy over direction (beam patterns) (He et al, 2015;Gupta et al, 2015;Fu et al, 2016). Rhinolophids and hipposiderids execute rigid and non-rigid pinna motions (Yin et al, 2017) accomplished by highly differentiated ear musculature (Schneider and Möhres, 1960). Experiments with robotic models have demonstrated target direction clues generated by rigid motions (Walker et al, 1998), and numerical predictions have shown changes in the nature of the beam patterns in response to non-rigid pinna motions (Gao et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Dynamic relationship between noseleaf and pinnae in echolocating hipposiderid bats

Zhang

Liu

Tang

et al. 2019

Journal of Experimental Biology

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Old World leaf-nosed bats (family Hipposideridae) can deform the shapes of their 'noseleaves' (i.e. ultrasonic emission baffles) and outer ears during echolocation behaviors. Prior work has shown that deformations on the emission as well as on the reception side can have an impact on the properties of the emitted/received sonar signals. The occurrence of the deformations on the emission and reception sides raises the question of whether the bats coordinate these two dynamic biosonar features to achieve synergistic effects. To address this question, simultaneous three-dimensional reconstructions of the trajectories of landmarks on the dynamic noseleaf and pinna geometries have been obtained in great roundleaf bats (Hipposideros pratti). These joint kinematics data on the noseleaf and pinnae have shown both qualitative and quantitative relationships between the noseleaf and pinna motions: large noseleaf deformations (opening or closing) tended to be associated with nonrigid pinna motions. Furthermore, closing deformations of the noseleaves tended to co-occur with closing motions of the pinna. Finally, a canonical correlation analysis of the motion trajectories has revealed a tight correlation between the motions of the landmarks on the noseleaf and both pinnae. These results demonstrate that the biosonar system of hipposiderid bats includes coordinated emission and reception dynamics.

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Horseshoe bats and Old World leaf-nosed bats have two discrete types of pinna motions

Cited by 14 publications

References 22 publications

Fast-moving bat ears create informative Doppler shifts

Fast-moving bat ears create informative Doppler shifts

Biomimetic detection of dynamic signatures in foliage echoes

Dynamic relationship between noseleaf and pinnae in echolocating hipposiderid bats

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