Re: Guide for anti-AATers
pete (VINCENT@REG.TRIUMF.CA)
8 Nov 1995 21:32:52 GMT
Benjamin H Diebold (bdiebold@minerva.cis.yale.edu) sez:
`pete (VINCENT@REG.TRIUMF.CA) wrote:
`: Benjamin H Diebold (bdiebold@minerva.cis.yale.edu) sez:
`: `How do you explain the other animals that swim and dive, but that still
`: `have hair? There are many mammals that spend varying amounts of time in
`: `the water, but yet have hair. Why wouldn't the same selective advantage
`: `in less body hair apply to them?
`: I don't think you'll find any with hair. Fur, they have. Considerably
`: different. Fur is a definite advantage for an aquatic animal,
`: whereas hair is probably just a nuisance, and possibly a serious
`: liability. It's not thick enough to insulate, nor oily enough
`: to shed water.
`Is there some qualitative difference between the hair on my back and the
`hair on a chimp's back, beside the fact that he has more of it?
No, chimps have hair, like us only more and longer.
`If there is no real qualitative difference, then there's just a continuum
`of haired (furry) to hairless (naked), in which case I don't understand
`why my original point is inaccurate.
Fur is a much more serious coating. There are specific technical
distinctions which I don't know offhand, but generally, fur is
more dense, and can be enlisted to provide a relatively waterproof
insulating layer.
`If there is such a difference, then when in the pre-Aquatic Ape stage of
`hominid evolution did fur become hair, and therefore something needing
`sloughing off as opposed to something worth keeping?
That would be difficult to say for certain because of the
uncertainties in the primate evolutionary tree, and the
inconvenientfact that hides don't fossilize well, but my
totally unsupported speculation would be that our ancestors
have been hairy rather than furry for at least 30My.
`Finally, if fur is such an advantage to aquatic animals, why don't
`whales, dolphins, or even fish have fur? In fact, it looks like very,
`very few aquatic animals have fur. Did their ancestors all start out with
`hair instead of fur, too (assuming your qualitative difference between
`hair and fur)?
That's one possibility. There are many furry aquatic mammals, and
the quality of their fur made them so much in demand that several
have been hunted almost to extinction.
--
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vincent@triumf.ca <== faster % Pete Vincent
vincent@freenet.vancouver.bc.ca % Disclaimer: all I know I
% learned from reading Usenet.
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