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Re: Aquatic ape theory
chris brochu (gator@mail.utexas.edu)
14 Oct 1995 17:43:38 GMT
In article <45o74k$45k@scotsman.ed.ac.uk> , jamesb@hgu.mrc.ac.uk writes:
>Yes, I should have been a bit clearer here. What I meant was that the
>elephants in Africa didn't grow their hair back. I reckon the real answer
>here is that hair only works as an insulator when dry, whereas
>subcutaneous fat works both when dry or wet, so if an animal species
>loses its hair and develops sub-cutaneous fat in an aquatic environment
>and then returns to the land, the selective pressure to re-grow the hair
>for insulation is reduced by the fat layer's presence. However, in
>extremely cold conditions both are needed for insulation. Hence, the
>wooly mammoth and the nude elephant. Are elephants directly descended
>from wooly mammoths or are they cousins?
>
Firstly, we are both making some grand assumptions when we suggest that
Mammuthus "regained" its hair. The fact is this : WE HAVE NO WAY TO
KNOW WHEN, AND WHERE, PROBOSCIDEANS LOST THEIR FUR. Period. For all we
know, all proboscideans were hairy until the divergence of extant
lineages, and mammoth hair could be a plesiomorphic trait. We do not
know.
Mammuthus is, I believe, more closely related to the Indian elephant than
to the African (correct me if incorrect). Still, we cannot state that
the earliest proboscideans were hairless, because the skin was not
preserved.
chris
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