Re: Otters Keep Warm With Hair, Not Fat

"Lee Olsen" <paleocity@xxxxxxxxxxx> wrote in message
news:1124485367.461827.294020@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

> > Yes, Richie, otters are smaller than humans, and they don't live in the
tropics... Sigh...

> Tropical otters http://www.wwfguianas.org/feat_spec_giant_otter.htm

Yes, of course. Sorry, I must have been in a hurry (as always when I'm
reading Travsky's (usu.biased & uninteresting) posts). Yes: it seems that SC
fat (too heavy) is no option for rel.small-sized fast riverrine semi-aquatic
divers. Also in deeper divers, the water pressure reduces the air layer in
the fur, eg, sea-otters spend 1-2 hrs per day pruning their fur (eg,
bringing air into the underfur). IOW, they might be at least 6 possible
water-related partial explanations why our ancestors lost the fur, and
otters didn't: our littoral ancestors were always tropical, were larger,
spent (most?) time in salt water, dived more slowly, & possibly they dived
deeper &/or spent more time in the water. Perhaps the necessary
swimming-speed (pisci- vs omnivore) was most important here? Babirusas are
about as heavy as humans & about as hairy & tropical.

--Marc
______

> >
http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-1-2005081
8-23295600-bc-us-otters.xml
> > >
> > > PHILADELPHIA, Aug. 18 (UPI) -- Otters -- unlike polar bears, seals,
> > dolphins
> > > and whales -- do not have a thick layer of body fat to keep warm,
> > according
> > > to U.S. researchers.
> > >
> > > Otters rely instead on a few unique adaptations -- their fur and the
> > densely
> > > packed layer of specially adapted underhairs.
> > >
> > > Using scanning electron microscopy and polarizing light microsopy,
John
> > W.
> > > Weisel, of the University of Pennsylvania School of Medicine,
examined
> > the
> > > structure of these hairs for clues to their exceptional insulation
> > abilities.
> > >
> > > They found that the cuticle surface structure of the underhairs and
base
> > of the
> > > less-abundant guard hairs are distinctively shaped to interlock, with
> > > wedge-shaped fins or petals fitting into wedge-shaped grooves between
> > fins of
> > > adjacent hairs.
> > >
> > > The findings are published in the Canadian Journal of Zoology.
>


.

Relevant Pages

  • Re: Otters Keep Warm With Hair, Not Fat
    ... >>> Yes, Richie, otters are smaller than humans, and they don't live in the ... > the fur, eg, sea-otters spend 1-2 hrs per day pruning their fur (eg, ... > spent time in salt water, dived more slowly, & possibly they dived ... > about as heavy as humans & about as hairy & tropical. ...
    (sci.anthropology.paleo)
  • Re: Otters Keep Warm With Hair, Not Fat
    ... >>> Yes, Richie, otters are smaller than humans, and they don't live in the ... > the fur, eg, sea-otters spend 1-2 hrs per day pruning their fur (eg, ... > about as heavy as humans & about as hairy & tropical. ... anything that requires other explanations. ...
    (sci.anthropology.paleo)
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