Echolocation in Bats

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Echolocation in Bats
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Questions

• What is the Behavior?
• What is the Adaptive Signficance?
• What is the Phylogenetic Context?
• What is the Natural History of the Species?
• Amenity to study / morpho specializations
• What is the neural basis of the behavior?

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Chiroptera
Flight - forelimb modifications Reversed hip
joint and knees for hanging upside down Claw
tendons Cranial features (large degree of
variance) Tragus in ear Megachiropterans (Old
World fruit eating bats) Microchiropterans
(echolocating bats) (PHYLOGENETIC controversy -
convergence) Eocene
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Bat Wings
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Characters
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Premaxillae
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Megachiropterans
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Flying Foxes
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Microchiropterans
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more
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more
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more
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Echolocating Animals
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Crappy Animations
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Need to know something about sound
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Sound

• Frequency (Hz) (f 1/T in rads Omega)
• Time wavelength (T)
• Amplitude (A)
• Phase (O)
• ln y A(sin(OmegaT O)

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Fourier

• Decomposition of a waveform or function into
  sinusoids of different frequency that sum to the
  original waveform.

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Clicks are special
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Trumpet and Trombone
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Other Uses for Fourier Transforms
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Information Content
Time varying
Build sonogram
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Sonogram
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Filtering
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Harmonics
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Frequency, objects, and power

• Area under the curve is power
• Echos and object size
• Temporal information, doppler shifts
• Ambient Noise
• Propagation of sound
• COCHLEA

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Bat Call Types - CF/FM/CFFM
Habitat, ranging, Food type
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Studying Bats
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Insectivorous bats
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Movie number 2
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Movie 3
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Psychophysics
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Screaming and Hearing
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Call Types
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CF/FM call
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Ascending
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Cortex