Migration information

From: Jennifer Philips (jphilips@hawaii.edu)
Date: Tue Feb 05 2002 - 19:27:56 EST


Hello,

   My name is Andrew Halford I am a third year science student at
the
university of New Brunswick. I am writing a paper on the
migration aspect of
whale behavior. I have been able to find some information on the
actual
migration patterns. however very little information on why they
evolved the
behavior and the evolutionary significance of the behavior. I was
wonder if
you could point me in a direction to find such information.

          Thanks, Andrew Halford

Andrew,

If you have access to good library resources, I would try
searching for older papers postulating explanations for baleen
whale migration. The current, widely accepted idea is that whales
must be in warmer waters to give birth to their young, but cannot
find sufficient food in the warmer waters, and so move north to
feed. This movement between breeding/calving areas and feeding
areas has thus evolved into a seasonal migration for many
species. However, there is some evidence that there are really no
strong selective pressures to back this up - that is, the young
of baleen whales should be able to handle cold waters just fine,
and in fact the young of many cetacean species are born in very
cold waters, including a few of the baleen whales. Instead, the
explanation for migration may simply be tradition, similar to the
force behind the long migrations of some song birds. As the
climates of the oceans changed over millions of years, areas of
high productivity (which whales thrive on) moved slowly north.
Whales, having started out in the waters of the Tethys Sea, may
have followed their prey northward over time, but remained loyal
to their original home ranges out of tradition. What we see today
may simply be the result of millions of years of evolution and
tradition.

There, you have two possible theories. If you have the Peter
Evans book "The Natural History of Whales and Dolphins" (1987),
you'll find some discussion of this there. Also, try searching
your library's old journal databases (Aquatic Fisheries is the
best index for cetacean research) for articles on migration.

Good luck!
Jen Philips



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