Measurements of the transmit beam patterns emitted by echolocating bats have previously been limited to cross-sectional planes or averaged over multiple signals using sparse microphone arrays. To date, no high-resolution measurements of individual bat transmit beams have been reported in the literature. Recent studies indicate that bats may change the time-frequency structure of their calls depending on the task, and suggest that their beam patterns are more dynamic than previously thought. To investigate beam pattern dynamics in a variety of bat species, a high-density reconfigurable microphone array was designed and constructed using low-cost ultrasonic microphones and custom electronic circuitry. The planar array is 1.83 m wide by 1.42 m tall with microphones positioned on a 2.54 cm square grid. The system can capture up to 228 channels simultaneously at a 500 kHz sampling rate. Beam patterns are reconstructed in azimuth, elevation, and frequency for visualization and further analysis. Validation of the array measurement system and post-processing functions is shown by reconstructing the beam pattern of a transducer with a fixed circular aperture and comparing the result with a theoretical model. To demonstrate the system in use, transmit beam patterns of the big brown bat, Eptesicus fuscus, are shown.
REFERENCES
1.
2.
R.
Müller
, “Numerical analysis of biosonar beamforming mechanisms and strategies in bats
,” J. Acoust. Soc. Am.
128
, 1414
–1425
(2010
).3.
D.
Griffin
, Listening in the Dark, The Acoustic Orientation of Bats and Men
(Cornell University Press
, London
, 1958
), p. 415
.4.
J. A.
Simmons
, “Acoustic radiation patterns for the echolocating bats Chilonycteris rubiginosa and Eptesicus fuscus
,” J. Acoust. Soc. Am.
46
, 1054
–1056
(1969
).5.
D.
Hartley
and R.
Suthers
, “The sound emission pattern of the echolocating bat, Eptesicus fuscus
,” J. Acoust. Soc. Am.
85
, 1348
–1351
(1989
).6.
K.
Ghose
and C.
Moss
, “The sonar beam pattern of a flying bat as it tracks tethered insects
,” J. Acoust. Soc. Am.
114
, 1120
–1131
(2003
).7.
K.
Ghose
, C.
Moss
, and T.
Horiuchi
, “Flying big brown bats emit a beam with two lobes in the vertical plane
,” J. Acoust. Soc. Am.
122
, 3717
–3724
(2007
).8.
A.
Surlykke
, S.
Boel Pedersen
, and L.
Jakobsen
, “Echolocating bats emit a highly directional sonar sound beam in the field
,” Proc. R. Soc. London, Ser. B
276
, 853
–860
(2009
).9.
Y.
Yovel
, B.
Falk
, C. F.
Moss
, and N.
Ulanovsky
, “Optimal localization by pointing off axis
,” Science
327
, 701
–704
(2010
).10.
N.
Matsuta
, S.
Hiryu
, E.
Fujioka
, Y.
Yamada
, H.
Riquimaroux
, and Y.
Watanabe
, “Adaptive beam-width control of echolocation sounds by CF-FM bats, Rhinolophus ferrumequinum nippon, during prey-capture flight
,” J. Exp. Biol.
216
, 1210
–1218
(2013
).11.
L.
Jakobsen
, J. M.
Ratcliffe
, and A.
Surlykke
, “Convergent acoustic field of view in echolocating bats
,” Nature
493
, 93
–96
(2014
).12.
L.
Jakobsen
, S.
Brinkløv
, and A.
Surlykke
, “Intensity and directionality of bat echolocation signals
,” Front. Physiol.
4
, Article No. 89, 1
–9
(2013
).13.
L.
Jakobsen
and A.
Surlykke
, “Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit
,” Proc. Natl. Acad. Sci. U.S.A.
107
, 13930
–13935
(2010
).14.
L.
Jakobsen
, E. K. V.
Kalko
, and A.
Surlykke
, “Echolocation beam shape in emballonurid bats, Saccopteryx bilineata and Cormura brevirostris
,” Behav. Ecol. Sociobiol.
66
, 1493
–1502
(2012
).15.
A.
Surlykke
, L.
Jakobsen
, E. K. V.
Kalko
, and R. A.
Page
, “Echolocation intensity and directionality of perching and flying fringe-lipped bats, Trachops cirrhosus (Phyllostomidae)
,” Front. Physiol.
4
, Article No. 143, 1
–9
(2013
).16.
R.
Müller
, “A numerical study of the role of the tragus in the big brown bat
,” J. Acoust. Soc. Am.
116
, 3701
–3712
(2004
).17.
R.
Müller
and J. C. T.
Hallam
, “Knowledge mining for biomimetic smart antenna shapes
,” Rob. Autom. Syst.
50
, 131
–145
(2005
).18.
D.
Vanderelst
, F.
De Mey
, H.
Peremans
, I.
Geipel
, E.
Kalko
, and U.
Firzlaff
, “What noseleaves do for FM bats depends on their degree of sensorial specialization
,” PLoS ONE
5
, e11893
(2010
).19.
D.
Vanderelst
, J.
Reijniers
, J.
Steckel
, and H.
Peremans
, “Information generated by the moving pinnae of Rhinolophus rouxi: Tuning of the morphology at different harmonics
,” PLoS ONE
6
, e20627
(2011
).20.
D.
Vanderelst
, R.
Jonas
, and P.
Herbert
, “The furrows of Rhinolophidae revisited
,” J. R. Soc. Interface
9
, 1100
–1103
(2012
).21.
D.
Vanderelst
, Y.
Lee
, I.
Geipel
, E.
Kalko
, Y. M.
Kuo
, and H.
Peremans
, “The noseleaf of Rhinolophus formosae focuses the frequency modulated (FM) component of the calls
,” Front. Physiol.
4
, 1
–8
(2013
).22.
P. W.
Moore
, L. A.
Dankiewicz
, and D. S.
Houser
, “Beamwidth control and angular target detection in an echolocating bottlenose dolphin (Tursiops truncatus)
,” J. Acoust. Soc. Am.
124
, 3324
–3332
(2008
).23.
L. N.
Kloepper
, P. E.
Nachtigall
, M. J.
Donahue
, and M.
Breese
, “Active echolocation beam focusing in the false killer whale, Pseudorca crassidens
,” J. Exp. Biol.
215
, 1306
–1312
(2012
).24.
J.
Starkhammar
, M.
Amundin
, J.
Nilsson
, T.
Jansson
, S. A.
Kuczaj
, M.
Almqvist
, and H. W.
Persson
, “47-channel burst-mode recording hydrophone system enabling measurements of the dynamic echolocation behavior of free-swimming dolphins
,” J. Acoust. Soc. Am.
126
, 959
–962
(2009
).25.
J. W.
Shaffer
, D.
Moretti
, S.
Jarvis
, P.
Tyack
, and M.
Johnson
, “Effective beam pattern of the Blainville's beaked whale (Mesoplodon densirostris) and implications for passive acoustic monitoring
,” J. Acoust. Soc. Am.
133
, 1770
–1784
(2013
).26.
W.
Au
and J.
Simmons
, “Echolocation in dolphins and bats
,” Phys. Today
60
, 40
–45
(2007
).27.
M.
Gillette
and H.
Silverman
, “A linear closed-form algorithm for source localization from time-differences of arrival
,” IEEE Signal Process. Lett.
15
, 1
–4
(2008
).28.
O.
Akay
and G.
Boudreaux-Bartels
, “Fractional convolution and correlation via operator methods and an application to detection of linear FM signals
,” IEEE Trans. Signal Process.
49
, 979
–993
(2001
).29.
J.
DiCecco
, J. E.
Gaudette
, and J. A.
Simmons
, “Multi-component separation and analysis of bat echolocation calls
,” J. Acoust. Soc. Am.
133
, 538
–546
(2013
).30.
L. B.
Jackson
, Digital Filters and Signal Processing with MATLAB Exercises
, 3rd ed. (Klewer Academic
, Norwell, MA
, 1995
), pp. 323
–372
.31.
ANSI S1.26-1995
(R2009): Method for Calculation of the Absorption of Sound by the Atmosphere
(American National Standards Institute
, New York
, 2009
).32.
W. I.
Futterman
, “Dispersive body waves
,” J. Geophys. Res.
67
, 5279
–5291
, doi: (1962
).33.
T.
Bobach
and G.
Umlauf
, “Natural neighbor concepts in scattered data interpolation and discrete function approximation
,” in Proceedings of Visualization of Large and Unstructured Data Sets
(2007
), pp. 23
–35
.34.
J. A.
Simmons
, M. B.
Fenton
, W. R.
Ferguson
, M.
Jutting
, and J.
Palin
, Apparatus for Research on Animal Ultrasonic Signals
(Royal Ontario Museum
, Toronto
, 1979
), p. 10
.35.
L. B.
Jackson
, “Frequency-domain Steiglitz-McBride method for least-squares IIR filter design, ARMA modeling, and periodogram smoothing
,” IEEE Signal Process. Lett.
15
, 49
–52
(2008
).36.
S.
Brinkløv
, E. K. V.
Kalko
, and A.
Surlykke
, “Intense echolocation calls from two ‘whispering’ bats, Artibeus jamaicensis and Macrophyllum macrophyllum (Phyllostomidae)
,” J. Exp. Biol.
212
, 11
–20
(2009
).37.
A.
Surlykke
and E. K. V.
Kalko
, “Echolocating bats cry out loud to detect their prey
,” PLoS ONE
3
, e2036
(2008
).38.
R.
Urick
, Principles of Underwater Sound
, 3rd ed. (McGraw-Hill
, New York
, 1983
), p. 43
.2014
U.S. Government
You do not currently have access to this content.
