Humpback whale breeding/birthing

From: Pieter Folkens (animalbytes@earthlink.net)
Date: Tue Mar 25 2003 - 12:18:53 EST

  • Next message: Pieter Folkens: "Whale Diversity"

    Dear Heidi:

    Thanx for sharing the story of your experience.

    Although it is possible you heard a newborn, 22 March is a bit late for
    humpback whale births. The peak of births occur in January. The bell
    curve begins in December and can extend into March. The calves need to
    float around the islands for a couple of months bulking up before
    heading off with the migration. Although an individual whale is known
    to make the Sitka-to-Maui run in under a month, it is unlikely a
    cow/calf pair can move that fast going north. We see the cow/calf pairs
    on the Southeast Alaska feeding grounds beginning in May. A calf born
    in late March would not make it to the feeding grounds until well into
    July, and that would be very tough on the mother.

    The one humpback birth I witnessed (in Madagascar) involved quite a bit
    of surface rolling and splashing by the mom. You did not mention
    hearing a lot of splashing. Rather, what I think you heard was a bull
    whale trying to interest a cow.

    It is quite possible that the sounds you heard came from a whale,
    considering the conditions at the time. We can hear underwater whale
    vocalizations from the surface surprisingly easily.

    Males on the breeding grounds engage in an interesting dominance/mate
    attraction display commonly called "singing." The sound they make can
    be described as similar to 'crying.' The humming noises could also have
    been whale social sounds. A male performing this act will point it's
    snout towards the bottom, float very still, and pass air within the the
    tubes between the blow hole and the lungs. You can make similar sounds
    doing the same thing (that is manipulating air between your lungs and
    throat).

    The timing is right too. Several weeks after giving birth, a female
    becomes 'receptive' to males. Competition between males increases
    during this time as one tries to get his chance with a cow.

    The gestation (length of pregnancy) is thought to be around eleven
    months. Some have argued that it is longer since females typically do
    not have a calf every year. However, there is one cow on record which
    had 4 calves in 5 years. A 10-11 month scenario fits nicely into the
    observed behaviors as well.

    As for your question as to how whales find a place to give birth, it
    appears to be an innate behavior with some learned components. A
    pregnant cow needs to find warmer waters in which to give birth. A calf
    born on the feeding grounds (45-50F) would need a substantial layer of
    insulating fat (blubber) in order to survive. Otherwise, it would
    succumb rather quickly to hypothermia. A fat calf is much harder on a
    cow than a thin one. So the cow knows to migrate to tropical waters
    (80) for her own comfort and the survival of the calf.

    I find it interesting that these animals migrate no further than they
    need to. The characteristics of the breeding grounds are: on the edge
    of the tropics near land which provides protection from winds. Each
    population of humpbacks have their own places to go. In the eastern
    North Pacific the 'Polynesian" humpbacks are born in Hawaii and migrate
    to Southeast Alaska for summer feeding. The 'Mexicans' are born in the
    southern Sea of Cortez and the Tres Marias, and migrate to feeding
    grounds between central California and Oregon up as far as Vancouver.
    (Maui and the Tres Marias are on essentially the same latitude.)
    Humpbacks in other parts of the world conduct similar migrations. For
    example, those that feed off New England in the summer, breed in the
    Caribbean in winter. As for the learned components, the grown up calf
    returns to its birth place.

    One last thing: I hope you do more research on whales for yourself so
    that this amazing experience is followed by many more. You might
    consider visiting "your" whales on the feeding grounds in South East
    Alaska. If you need recommendations for a trip to AK, you may write me
    at this email address.

    Cheers,

    Pieter Folkens
    Alaska Whale Foundation

    On Monday, March 24, 2003, at 10:48 PM, Heidi Vaughn wrote:

    > Hi,
    > On Saturday March 22,2003, I was spending the night in a hotel on the
    > west coast of Maui, Hawaii. Our room was located right on the ocean
    > only a few feet from the water. In the morning we had been watching
    > whales out in the ocean swimming. At about 10:00 pm we heard what
    > sounded like a whale blowing water through it's blow hole. We
    > listened for about 2 hours because it sounded so close to us. The
    > evening was calm the ocean was calm and quiet. At around 12:30 am we
    > heard what sounded like a newborn baby crying. We also heard what
    > sounded like humming coming from the ocean.
    > My question is this, do you think we witnessed the birth of a baby
    > whale? Also can you give me some idea as to how these whales find a
    > place to give, how long they are pregnant and how long do they stay
    > with their babies after they are born? I have not done much research
    > on whales and I found this experience to be one of the most amazing of
    > my life.
    > Thank you for taking time to read this letter.
    > Heidi Vaughn
    >
    >
    >
    >
    >
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