Re: dino dental hygiene

[Dann Pigdon <dannj@alphalink.com.au>]

Jura writes: 

> I don't know of any fish that would be so daring, but
> there are birds that readily enter crocodile mouths to
> clean out the leftovers. _Pluvianus
> aegyptius_(Egyptian Plover) is the little bird in
> question...

Ah - that's the one.

> The obvious follow-up question to something like this
> is how would such a trait evolve? What suicidal little
> animal would decide to give such a thing a shot in the
> first place? 

The croc jaw-closing reflex is triggered by something touching the inner tip 
of the lower jaw. Steve Irwin used to demonstrate this by touching the 
trigger point with a stick. He could poke gently at the tongue or other 
areas of the jaw and get no similar response, but just a light touch on the 
inner part of the lower jaw tip triggered the reflex (even if the croc was 
half-asleep). 

Once a croc is blissfully snoozing in the sun with it's mouth open (a 
cooling mechanism I suspect), any small bird careful enough to avoid 
touching the reflex trigger point would be able to forage amongst sharpened 
ivory with relative impunity. However learning exactly where that trigger 
point was through trial and error could be a painful lesson indeed. 

___________________________________________________________________ 

Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com
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