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DOLPHIN
Dolphins have great appeal and their frolicking close off-shore
and their bow-riding give much pleasure to human observers. About the difference
between dolphins and porpoises there has been considerable confusion and
sometimes the same animal has been called by both names. There is, however, a
technical difference: a few species in the family Delphinidae have spade-shaped
teeth and these are the true porpoises. All the rest are dolphins All dolphins
and porpoises belong in the whale group (Order Cetacea). Generally, if it
is less than 3 metres in length, the animal will be regarded as a dolphin or porpoise.
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Dolphins, like whales, produce a wide variety of sounds. The most common are
high-pitched clicks and whistles. These serve as a means of communication about
which Man probably has much to learn. Dolphins also use sound as a kind of
sonar, as do bats, in which sounds are bounced off objects and the location of
such objects (or prey) can be determined by the nature of the returned
signals.
Of all dolphins it is the Bottle-nosed Dolphin which is most famous for its association with Man both in the wild and in captivity. Dolphins not only entertain but have of recent years, in the wild and in close contact with humans, been used for therapy of various kinds.
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