Sleep in whales

From: Phil Clapham (
Date: Mon Mar 03 2003 - 13:39:41 EST

  • Next message: Phil Clapham: "Blue whale reproduction"

    Hi Brian:

    Interesting question. The whole issue of sleep in whales, dolphins and
    porpoises is a bit of an unknown, but here's what we do know...

    While I don't know of anyone who has ever studied sleep in killer
    whales, scientists have hooked up an EEG to dolphins. What happens
    there is interesting: half of the brain seems to sleep at a time, with
    the two havles switching off. This makes sense, because all cetaceans
    (whales, dolphins and porpoises) are violuntary breathers - that is,
    they have to think to breathe. We don't - we breathe automatically.
    But a diving animal that spends lots of time underwater obviously needs
    to have control over its breathing. Therefore, if the entire brain shut
    down (as it does in people) the whale would presumably forget to
    breathe. So what we think currently is that half the brain sleeps while
    the other half stays alert to keep track of respiration. This is
    probably what all whales and dolphins (including killer whales) do, but
    no one knows for sure.

    And yes, all whales hold their breath when they're underwater.

    Phil Clapham

    Brian Barker wrote:
    > Do Orca whales sleep? And if they do sleep, do they
    > hold their breath under water while they do?
    > Brian
    > __________________________________________________
    > Do you Yahoo!?
    > Yahoo! Tax Center - forms, calculators, tips, more


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

    tel. 508 495-2316 fax 508 495-2066 email:

    This archive was generated by hypermail 2b30 : Tue Mar 04 2003 - 10:06:38 EST