blue whales..

From: Howard Garrett (howard@orcanetwork.org)
Date: Sat Nov 20 2004 - 19:07:18 EST

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    >how old do blue whales usually live to be? can they live to be very old
    >like elephants? it must take quite a while for them to reach such an
    >enormous size.
    >jake

    That's a very good question, for which there is very little actual data to
    answer. Upon researching the question I found that estimates range from a
    conservative estimate of 50 years longevity, to 110 years or more. Since
    baleen whales don't have teeth, which can be used to estimate age by
    counting the layers of tooth enamel, there is no way to determine the age
    of a blue whale either dead or alive. The best way is to photo-identify a
    cross section of individuals continually for many years, at least 15-20
    years to get a good sense of mortality rates in comparison to overall
    population, as has been done with killer whales. Average and maximum
    lifespans can be deduced from these demographic statistics. There are such
    studies being done with blue whale populations, (see the Mingan Island
    Cetacean Study, at http://www.rorqual.com/, for instance) but I'm not aware
    of any published results to date.

    Howard Garrett
    Orca Network
    Greenbank WA
    (360) 678-3451
    www.orcanetwork.org
    howard@orcanetwork.org



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