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Re: Dino Vocalizations: My Previous Attachment
> Hypothesis: Hadrosaurs used their crests as resonance chambers to produce
> low frequency vocalizations which their predators could not hear.
Wouldn't this have been of limited utility? I believe the physics
says the low-frequency emissions would be hard to directionally
localize since multiple detectors have to be spaced at a good
fraction of the wavelength, at least, ie the detector has to be
comparable in size to the (folded)generator. This is maybe problematic
using only ears. I recall that the lower frequency range
of human direction finding is comparatively high, in the 100s of Hz.
Just shouting "Predator here!" doesn't help much, if other non-local
hadrosaurs can't localize the direction to determine which way
to flee (or rally for defense?!)
Worth thinking about, IMHO.
[ You might want to keep in mind that making noises predators can't
hear is likely to be quite separate from making alarm calls. An
animal is better off if its predators *can* hear alarm calls because
said calls tell the predator that he's been spotted. Predators are
less likely to pursue prey if they "know" they've been detected and
are thus in for a chase. As potential prey, you want to make noises
your predators can't hear when those noises serve purposes other
than alerting your neighbors of a predator, however. -- MR ]
PS:There's some analysis of vocalization pitch in "Dynamics of Dinosaurs
and Other Extinct Giants," R. McNeill Alexander, Columbia University
Press, 1989, in Barnes and Nobles everywhere.