Subject: Polar bear hair

Mike Williamson (
Sun, 7 Jun 1998 08:02:35 -0400 (EDT)

---------- Forwarded message ----------
Date: Fri, 5 Jun 1998 20:16:18 -0700
From: Elaine Humphrey <>
Reply-To: Marine Mammals Research and Conservation Discussion
Subject: Re: polar bear hair

The case against solar heated polar bears, with their black skin and fibre
optic hollow hair is further substantiated by grizzely bear hair. I have a
series of scanning electron micrographs comparing the hair of these two
bears and they are very similar, both with the hollow medulla.  A more
plausible explanation might be insulation.  Many of the artic mammals and
high altitude mountainous mammals have hollow hair.  For example, cariboo
hair has a hollow honeycomb structure, which not only gives good insulation
for the cariboo, but some Inuit friends assure me, makes the warmest fur

Marine mammal hair is of peculiar interest.  It comes in many different
forms. Sea Otter hair is the neatest.  It is particularly sculptured, so
much so, that it gives the impression of being able to zip lock together
much like the barbules on a bird's feather.  Since sea otters have very
little fat, they rely heavily on a layer of air next to the skin for
insulation.  Much of their time is spent grooming and putting the air back.
If you watch them dive, you can see the air rising to the surface from
under their fur.  When you see the structure of the hair, you realise how
the hair can form a light seal to trap the air.  While sea otters have the
reputation of having the densest fur, their cousins river otters, ferrets
and mink have similar sculpturing to their hair.

For the past few years, I have been making scannning electron micrograph
pictures of many different mammal hairs. One project was for comparison
with hair found in the stomach of a dead transient killer whale washed up
in British Columbia.

A juvenile gray whale died and was washed up on Second Beach in Vancouver
about three years ago and when I went to pick up some whale lice for the
SEM, I noticed it had individual hairs dotted sparcely around the front of
its head.  When I made scanning electron micrographs of the hair, it
suggested a large medulla which might be filled with sensory neurons such
as in the smaller medulla of seal whiskers. But I can't be sure until I try
transmission electron microscopy and look at the cellular structure.
Unfortunately, I have had no specimens.  With the new field season coming,
should anyone come across a beached animal which has just died, especially
if it is a gray whale, would you please preserve a sample of any hair that
you find and pass it on to me?
Many thanks

Dr. Elaine Humphrey
Biosciences Electron Microscopy Facility
University of British Columbia
6270 University Blvd
Vancouver, BC
Phone: 604-822-3354
FAX:   604-822-6089