Orcas and Sharks

From: Kim Marshall (kimm@oceanalliance.org)
Date: Sun Dec 15 2002 - 13:50:50 EST

  • Next message: Kim Marshall: "Blue Whales"

    Question:
    I have a science fair project that I am working on. I was hoping you could
    be of some help. My question is: are sharks or Killer whales a bigger
    threat to humans? I hope that you can help me!

    Reply:
    Dear Whale Lover:
    I believe that any wild animal can be a threat to a human if the human
    threatens the animal. Otherwise most animals are not interested in us at
    all. If you study animal behavior you will learn why sharks and other
    predatory animals like killer whales sometimes do things that might harm a
    human being. For instance, sharks instinctively hunt for turtles and if
    there is a bobbing human on the surface of the water splashing around it
    could be mistaken as a turtle. I donšt believe that any animal
    intentionally attacks a human. It usually is a result of the human doing
    something to make the animal afraid.

    Please search WhaleNet for more information at http://whale.wheelock.edu.
    Here is a website that will provide you with information about orcas (killer
    whales): http://www.marinelab.sarasota.fl.us/~rhueter/sharks/shark.phtml,
    and below I have added some general information.

    Orca whales, or killer whales, are medium sized whales which live in all
    oceans of the world. The only limitations to where they can be found is
    food (they canšt live in places where no food is available) and surface ice
    (they need to breathe, so ice canšt be covering too large of an area).
        Orcas are recognizable by the distinct white markings on their mostly
    glossy black bodies. A killer whale has an oval-shaped eye patch behind
    each eye. Its chin and chest are also white. This white patch extends into
    a white stripe down its belly to its tail. From an orcašs belly, the white
    stripe extends up into white patches on the lower part of the whalešs sides,
    between the tail and the dorsal fin (the fin on top of the whalešs back).
    There is one more identifying mark, and that is the whitish patch on the
    orcašs saddle, or the place right behind the dorsal fin. The color here
    varies between white and different shades of gray. Every orca whalešs
    markings are different, and some have less or more white than others. There
    are even a few orcas that are all black or all white!
        Male orcas grow up to between 27 feet and 33 feet long. Females are a
    little smaller. They are typically about 23 feet long, but the largest
    female orca found was over 28 feet long. One amazing thing about orcas are
    the sizes of their dorsal fins. Females have dorsal fins up to 3 and 1/3
    feet tall, and males can have even larger fins, up to six feet!
        Even though orcas are not the largest whale, they are fierce predators.
    They usually eat fish, especially herring and salmon, but if they are
    hungry, they will eat almost anything including seabirds, sea turtles, seals
    and sea lions, and even other whales. When they do attack other, larger
    whales, it is often because they cannot find other food.
        Orcas often hunt in packs, much like wolves. A pack will surround their
    prey so that it canšt swim away, and then they take bites of it until they
    kill it or until they are full. If they attack another whale, they choose
    the weakest whale they find and attack its lips, tongue, and belly.
    However, the large whales have a defense. They have huge, powerful tails,
    and can hit their attackers very hard. One person reported seeing a killer
    whale thrown 30 feet away from its prey!
        Orcas usually travel in pods, or groups, of 5 to 30 whales. However,
    sometimes they are solitary, while other times pods as large as 100 whales
    or even more have been seen! The leader of the pod is usually a mature
    female. Most whales, when they grow up, stay in their motheršs pod until
    she dies. When she dies, one of the older females may take over the
    leadership of the pod, or the pod may split, with two or more mature females
    taking on the leaderships of the new pods.
        In these pods, we can often see different types of behavior among the
    killer whales. Some of them are also seen in other whales. Some of the
    behaviors that killer whales perform are:

    1) Breaching: the whale jumps out of the water, headfirst, and lands on its
    belly or twists in the air to land on its side or back
    2) Flipper slapping: when the orca slaps the surface of the water with its
    flippers
    3) Lobtailing: the orca sticks its tail out of the water and slaps it onto
    the surface
    4) Spyhopping: in order to take a look around above water, the whale sticks
    its head and part of its chest out of the water. Sometimes several orcas
    will do this at the same time.
    5) Speed-swimming: the whale travels fast and most of its body leaves the
    water when it surfaces to breathe. Orcas can travel as fast as 34 miles per
    hour!
    6) Logging: a whole pod faces the same direction
    7) Dorsal fin slapping: The orca rolls onto its side and slaps the water
    with its dorsal fin

        Female orcas, or cows, are pregnant once every 3 to 8 years. A mother
    carries her baby, or calf, for 17 months before it is born. Most calves are
    born during the autumn. At birth, a newborn orca is 7 to 8 1/2 feet long
    and weighs about 390 pounds! Its white patches are not yet white--they are
    tan or yellow in color until it gets older. It nurses its motheršs milk
    (remember that whales are mammals and feed just like human babies do) for
    several months, and begins eating solid food at about five months old. By
    nine months old, a baby orca eats mostly solid food, though it may still
    nurse occasionally for a few months. At this point, the orca is eating an
    equivalent of 4 to 5 percent of its own body weight every single day.
    Imagine if you weighed 80 pounds--you would eat 3 to 4.5 pounds of food each
    day if you ate like an orca.
        Orcas are in danger from only one other animal--humans. Orcas are not
    usually hunted, and are not yet endangered, but they are sometimes killed by
    native peoples whose only food is meat from animals they can catch. They
    are also taken by commercial whalers occasionally if they are in the path of
    a hunt for another type of whale. More threatening, however, is pollution
    in the oceans. Chemicals from many different manufacturing and processing
    plants, and trash from companies and from everyonešs homes often end up in
    the oceans, where they can hurt all sea life. Chemical pollutants build up
    in the bodies of animals and are passed on to their offspring. Trash can be
    swallowed by sea life, or animals can get tangled up in it. So far, effects
    of chemical pollutants have not been seen in orcas, but they have been seen
    in other marine mammals and birds, including beluga whales and albatrosses.
    These pollutants cause birth defects in young animals, causing them to die
    before they are born or at a young age.
        To save the orcas and their environment from pollutants, you can help
    keep pollutants from getting into our oceans. You can use recycled,
    non-bleached paper for your schoolwork and for drawing, and you can help
    your parents recycle paper, plastic, glass, aluminum, and tin. In your area
    there may even be more things you can recycle. Use less water when you
    shower, brush your teeth, and wash clothes and dishes. This helps the
    environment by reducing the amount of energy used to move the water to your
    house. You can also write to your local politicians and ask them to vote for
    policies that will help the environment.
        Last but not least, keep learning more about whales and the environment
    through organizations like Whale Conservation Institute and through your
    local school and public libraries! The more you learn, the more you can
    help other people learn about whales and the things that are threatening
    their survival. It is only with the help of special, interested and
    dedicated kids like you that we can all change the world.

    Bibliography (you can look for these books in your local libraries):

     1) Carwardine, Mark. 1995. Whales, Dolphins, and Porpoises. Dorling
    Kindersley, New York, 256 pp.

    2) Cousteau, Jacques-Yves and Yves Paccalet. Jacques Cousteau Whales.
    Harry N. Abrams, Inc., New York, 280 pp.

    3) Leatherwood, Stephen et al. 1988. Whales, Dolphins, and Porpoises of
    the eastern north pacific and adjacent arctic waters. A guide to their
    identification. Dover Publications, Inc., New York, 245 pp.

    4) IUCN (The World Conservation Union). 1991. Dolphins, Porpoises, and
    Whales of the World. The IUCN Red Data Book. Cambridge, U.K., 429 pp.

    Happy Holidays!

    Kim

    Kim Marshall
    Executive Director
    Ocean Alliance (Whale Conservation Inst. & the Voyage of the Odyssey)
    191 Weston Road, Lincoln, MA 01773
    781.259.0423 ext. 14 fax 259.0288
    www.oceanalliance.org www.pbs.org/odyssey
    Please support our efforts to conserve whales and their ocean environment
    through research and education :)



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