Reproduction and mating

From: Phil Clapham (pclapham@whsun1.wh.whoi.edu)
Date: Thu Mar 13 2003 - 07:56:59 EST

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    Hi

    Depends on exactly what you mean by the question. Since they're
    mammals, they give birth to live young and nurse those young with milk.
      Female whales give birth to single calves every 1-5 years, depending
    on the species, and calves stay with their mothers for 6-12 months in
    baleen whales, and for many years in the case of sperm whales.

    If you mean how do whales have sex, pretty much the same way other
    mammals do. Sort of. In males, the penis is rectractile (it's inside
    the body most of the time, to reduce drag in the water), but is extruded
    for mating. It's (hello) large, varying from around 5-8 feet depending
    on the species (for the record, right whales have the longest penis and
    the biggest testes in the animal kingdom; the latter weigh one ton!) In
    species where mating has been observed, it is the tip of the penis that
    enters the female's vagina (which is on the underside of the animal
    around 2/3 to 3/4 of the way back towards the tail). The penis is very
    flexible and can "reach over" to insert while the whales are side by side.

    Mating systems vary among species. Humpback whale males fight very
    aggressively for females, while right whales don't; instead, they engage
    in what's termed "sperm competition", where a female will mate with two
    or males serially (occasionally simultaneously - it's physically
    possible in whales and we've seen it!) and each male will essentially
    compete by trying to outdo the other(s) in the volume of sperm delivered
    to the vagina. Hence the huge testis size in right whales - they're
    trying to outcompete other males at the level of sperm production. This
    is a common mating system in many animals (to name just two species,
    chimpanzees and dragon flies also do it).

    Now you know!

    Phil Clapham

    laudra maurille wrote:
    > How do whales reproduce?

    -- 
    

    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: pclapham@whsun1.wh.whoi.edu



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