Re: downy dinos

[Waylon Rowley <whte_rbt_obj@yahoo.com>]

--- Jeff Hecht <jeff.hecht@sff.net> wrote:

> There are a number of biological examples of light
> guiding, generally 
> over quite short distances. One example lies within
> the rods and 
> cones in the retina, which guide light along their
> length to the 
> light-sensing regions at the backs of the cells. My
> point was that 
> polar bear hair is not fiber-optic, and that the
> mechanism of 
> collecting exterior light to "pipe" through a hair
> or feather to the 
> skin is unrealistic. In addition, true 'fiber-optic'
> light guiding 
> requires a core of higher refractive index than the
> surrounding 
> material -- not a hollow core. It is possible to
> guide some light 
> through a hollow core (which has a lower refractive
> index than the 
> surrounding material), but it's not as efficient as
> guiding light 
> through a fiber.

What is the role of UV-absorbing keratin in the
epidermis? Does keratin play a vital role in calcium
synthesis? I can't seem to find anything about it on
the net. Certainly birds and fuzzy dinos must have had
some way to get their daily dose of full spectrum
light (which is critical to the health of all
reptiles).....

Cheers,

Waylon Rowley   

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