Re: Question: Why did birds lose their teeth?

[Martin Baeker <martin.baeker@tu-bs.de>]

thanks for that answer,

I thought that there are two questions here:

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

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?

Martin.

> 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.
>
> —Mike
>
>
> 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
>
> https://plus.google.com/+MichaelHabib/about
> biologyinmotion@gmail.com
> (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.
> >
> >                   Priv.-Doz. Dr. Martin Bäker
> >                   Institut für Werkstoffe
> >                   Technische Universität Braunschweig
> >                   Langer Kamp 8
> >                   38106 Braunschweig
> >                   Germany
> >                   Tel.: 00-49-531-391-3065   <===  NEW phone number!
> >                   Fax   00-49-531-391-3058
> >                   e-mail <martin.baeker@tu-bs.de>
> >                    
> > http://www.tu-braunschweig.de/ifw/institut/mitarbeiter/roesler1
> >                    http://www.scienceblogs.de/hier-wohnen-drachen

                   Priv.-Doz. Dr. Martin Bäker
                   Institut für Werkstoffe
                   Technische Universität Braunschweig
                   Langer Kamp 8
                   38106 Braunschweig
                   Germany
                   Tel.: 00-49-531-391-3065   <===  NEW phone number!
                   Fax   00-49-531-391-3058
                   e-mail <martin.baeker@tu-bs.de>
                   
http://www.tu-braunschweig.de/ifw/institut/mitarbeiter/roesler1
                   http://www.scienceblogs.de/hier-wohnen-drachen