Hello Ms. Marshall,
My daughter is in first grade and is starting to look up stuff on the
computer, she has a sheet of questions about whales and we are having
trouble answering two questions :How do whales find their way? And What
causes them to leave where they migrate?
Whales use a mechanism called echolocation to 'see' with their ears. They
direct a beam of click-like sounds and listen to the echoes that return from
objects in the path of the sound. If you direct a flashlight at something
in the dark, you illuminate the object with light and you can see it.
Whales can 'illuminate' a silent fish with sound in order to 'see' it. From
the returning sound, the whale learns the size, shape, speed, and direction
of the subject. Dolphins can even beam their sound waves into mud to find
hiding fish! (Seawater and flesh have approximately the same density, so the
sounds whales emit penetrate the flesh of submerged animals. It has been
suggested that whales can actually see the inside of their companions and
their prey. The resulting image might look like an ultrasound picture).
Fish can't hear the high pitched sounds, so they don't realize they are
being looked over. It has been postulated that some cetaceans, such as the
sperm whale, may even use strong pulses of sound to stun their prey!
³Toothed whales generally spend most of their time in shallow, coastal areas
and use sharp, high frequency sounds that don't travel very far through the
water before being converted into heat. Short, high-pitched, rapid sounds
used on objects in close proximity allow whales to hear the finer details.
Some types of baleen whales (like blue and fin whales) spend a lot of time
in deep, dark waters and use loud low frequency, long-ranging sounds to
communicate and navigate the seas. Low frequency sound can travel for long
distances, but only gives broader details. The distance traveled depends
largely on the depth and temperature of the ocean the sound is sent from
(temperature and pressure change the conductive properties of water).
Humpback whales on the east coast of the US travel from southern areas of
waters of the Dominican Republic where they give birth and mate up to their
feeding areas in the gulf of Maine and off the eastern coast of Canada.
Humpback whales of the Pacific migrate from the warmer waters of Mexico and
Hawaii to the rich feeding area off Alaska. It is believed that these
ancient paths are taught to the young via songs and memory and we have
noticed that calves that come to certain feeding areas with their mothers
will return the the same area the next year even if their mother doesn't.
Right whales in the northern hemisphere off the east coast travel from
southern Georgia and Florida to the feeding area in the Bay of Fundy. There
are less than 500 left of the Northern right whale.
Gray whales of the Pacific have the longest migration route where they
travel from Mexico to the Bering Sea (over 3000 miles). They are known at
times to take a short cut across deeper waters. They also migrate a shorter
distance via the Sea of Japan. (Evans, Peter., The Natural History of Whales
If you want to learn more about these subjects please visit WhaleNet¹s
search page http://whale.wheelock.edu/Search.html.
Thank you, I hope this information helps your daughter with her project.
Ocean Alliance (Whale Conservation Inst. & the Voyage of the Odyssey)
191 Weston Road, Lincoln, MA 01773
781.259.0423 ext. 14 fax 259.0288
Please support our efforts to conserve whales and their ocean environment
through research and education :)
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