grey whale migration

From: Phil Clapham (phillip.clapham@noaa.gov)
Date: Tue Oct 09 2001 - 09:43:28 EDT


Hi:

Actually, you may be surprised to learn that we really dont know for
sure why any whales migrate. The most popular theory is the one you
give, about the "advantage" of giving birth in warm water. Some people
think that all migratory whales benefit from warmer water in winter - in
other words, that what they lose by not eating for weeks they more than
make up by the lower cost of keeping warm in tropical waters. But a lot
of other people don't buy this idea, saying that even a calf has enough
blubber for it to live happily in cold water in winter.

Personally, I think that it doesn't relate to calves dying in cold water
in winter; it's maybe more that, because a calf born in warm water can
devote less energy to keeping warm than it would in high latitudes, it
can therefore devote MORE energy to growth. This would be a strong
selective advantage in evolutionary terms, because it might mean that a
strong calf grows up to be a strong adult and thus does much better when
it comes time for it to reproduce. But we just don't know!

Phil Clapham

Frogcepjd@aol.com wrote:
>
> Sir,
> I understand the importance of gray whale migration for the calf.
> Less blubber warm h20 etc. Is there a significance for an older
> gray?
> thank you JD
> frogcepjd@aol.com

-- 
The Society for Marine Mammalogy will be holding its 14th Biennial
Conference from 28 November to 3 December 2001, in Vancouver, BC.  Visit
the conference Web site at www.smmconference.org for full details of
this important meeting.

Phillip J. Clapham, Ph.D. Large Whale Biology Program Protected Species Branch Northeast Fisheries Science Center 166 Water Street Woods Hole, MA 02543, U.S.A.

tel. 508 495-2316 fax 508 495-2066 email: phillip.clapham@noaa.gov



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