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Re: Question: Why did birds lose their teeth?

Martin (and list):

I am having trouble finding that specific reference, as well, though a bit of 
quick math shows that tooth loss in birds can’t remove significant weight 
because the entire hard tissue skeletal system (teeth included) only accounts 
for about 25-35% of total body mass, of which half is water. By way of example, 
the total dry mass of both humeri in a mid-sized bird (390-500 gram range) 
ranges from about 0.7% to 1.2% of total mass. The teeth would presumably make 
up less mass than that of both entire humeri. The potential loss of mass from 
losing teeth is dwarfed by the body mass changes from simply burning fat and 
muscle in flight. During long migrations, some birds lose 50% of their body 
mass. Under those conditions, the lost of teeth is practically rounding error.


Michael Habib
Assistant Professor of Cell and Neurobiology
Keck School of Medicine of USC
University of Southern California
Bishop Research Building; Room 403
1333 San Pablo Street, Los Angeles 90089-9112

Research Associate, Dinosaur Institute
Natural History Museum of Los Angeles County
900 Exposition Blvd, Los Angeles, CA 90007

(443) 280-0181

On Mar 10, 2014, at 7:16 AM, Martin Baeker <martin.baeker@tu-bs.de> wrote:

> Dear all,
> I once learned that losing teeth was a weight-saving measure and thus
> a flight adaptation. There is this reference stating this  as a possibility
> http://www.newscientist.com/article/dn18248-early-birds-may-have-dropped-teeth-to-get-airborne.html#.Ux3HhdsjulM
> However, I seem to remember that there was some study showing that
> birds actually do not lose signifcant weight by replacing teeth with
> beaks - if anybody has a reference on this, I'd be grateful.
> Thanks a lot,
> Martin.
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