Re: Question: Why did birds lose their teeth?

[don ohmes <d_ohmes@yahoo.com>]

I do not claim this is testable (I have thought of one possible way, I will 
mention it later), but a plausible selective path to tooth loss in birds is 
clear. 

Think about this next time you are flossing -- small bipeds that cannot use 
their hands to clear stuck/snagged material from their mouths have a problem -- 
if they are volant, the problem is exacerbated. 

Fully optimizing wings (in birds) for flight logically and apparently demands 
losing the claws -- and a toothy bird is just that more likely to die from 
something a little too big to swallow, not to mention catching something too 
large in the first place! 

Perhaps there is a clear pattern in the data of 'first go the claws, then the 
teeth'? 


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On Mon, Mar 10, 2014 6:27 PM EDT Dann Pigdon wrote:

>On Tue, Mar 11th, 2014 at 1:16 AM, Martin Baeker <martin.baeker@tu-bs.de> 
>wrote:
>
>> 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.
>
>There may not have been a single source of selective pressure for loss of 
>teeth. A whole lot of 
>separate minor advantages may well have added up.
>
>Constantly shedding and replacing teeth might have been an expensive use of 
>calcium, for 
>instance, that could otherwise be used to stengthen bones against the rigours 
>of flight, or for the 
>production of hard-shelled eggs that were larger relative to body weight than 
>those of non-volant 
>theropods.
>
>The weight of the teeth themselves may not have been the only weight-saving 
>advantage either. 
>The lack of teeth might have allowed the jaw bones to become more slender, 
>making it possible to 
>make do with a much more light-weight skull. The jaw bones of tooth-bearing 
>creatures are 
>generally the toughest bones in the body (which is why jaw bones are so common 
>in the fossil 
>record). In some modern birds, the mandibles are little more than whispy 
>splints of bone once the 
>beak has been removed.
>
>-- 
>_____________________________________________________________
>
>Dann Pigdon
>Spatial Data Analyst               Australian Dinosaurs
>Melbourne, Australia               http://home.alphalink.com.au/~dannj
>_____________________________________________________________
>