Dinosaur hearing

[Guy Leahy <xrciseguy@sbcglobal.net>]

I don't think this item has been mentioned on the list
yet:
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1: Naturwissenschaften. 2005 Oct 18;:1-4 [Epub ahead
of print] 

Audiogram, body mass, and basilar papilla length:
correlations in birds and predictions for extinct
archosaurs.

Gleich O, Dooling RJ, Manley GA.

ENT Department, University of Regensburg,
Franz-Josef-Strauss-Allee 11, 93042, Regensburg,
Germany, otto.gleich@klinik.uni-regensburg.de.

The inner ear in the group of archosaurs (birds,
crocodilians, and extinct dinosaurs) shows a high
degree of structural similarity, enabling predictions
of their function in extinct species based on
relationships among similar variables in living birds.
Behavioral audiograms and morphological data on the
length of the auditory sensory epithelium (the basilar
papilla) are available for many avian species. By
bringing different data sets together, we show that
body mass and the size of the basilar papilla are
significantly correlated, and the most sensitive
frequency in a given species is inversely related to
the body mass and the length of the basilar papilla.
We also demonstrate that the frequency of best hearing
is correlated with the high-frequency limit of
hearing. Small species with a short basilar papilla
hear higher frequencies compared with larger species
with a longer basilar papilla. Based on the regression
analysis of two significant correlations in living
archosaurs (best audiogram frequency vs body mass and
best audiogram frequency vs papillar length), we
suggest that hearing in large dinosaurs was restricted
to low frequencies with a high-frequency limit below 3
kHz.

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Guy Leahy