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Re: Question: Why did birds lose their teeth?

On Mar 11, 2014, at 1:44 AM, Martin Baeker <martin.baeker@tu-bs.de> wrote:

> 1. Are bird beaks really weight saving compared to teeth?

As Jaime noted, beaks are often heavier.

> 2. If so, what might be an advantage of that? I think that the total
> weight loss is - as you write - small compared to body weight, but
> what about moment arms and the torque around the CoM during flight? Is
> that also small enough to be neglected?

Either way, the changes in the effective moment relative to the CoM (or perhaps 
more notably, the Center of Lift) are negligible. One way of looking at this is 
to consider how much change in wing sweep is required to accommodate the 
altered moment if the skull is lightened by 1-3% or so (which is probably a 
gross overestimate of the difference between teeth and beaks, but allows us to 
be conservative). The change in sweep is so small that it’s practically not 
even measurably (0.005 to .01 radians if one is generous with moment arms and 
skull mass).



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