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The
whale and the dolphin are cousins. Whales, dolphins and porpoises all
belong to the same family known as Cetacea. Isn’t
it amazing that the small porpoise measuring less than one and a half meters
in length and the thirty five meter blue whale, which weighs up to
one hundred and twenty tones, belong to the same family? Members
belonging to this family are designed for a life only in water. If they
are stranded on land, they will be crushed by their own weight. All
cetaceans breathe by swimming to the surface. Their nostrils or blowhole
are situated on the top of the head. Does that solve the mystery of the
dolphin’s whistle?
Dolphins
and porpoises are among the smaller whales. Dolphins have sleek bodies,
with a large fin on the back. Their jaws are like beaks. They move
around in schools, following ships. They swim at a speed of thirty-two kilometers
an hour and can make a fascinating display of leaping into the
water. Dolphins have horizontal tails. When they swim, their bodies move
up and down. |
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Porpoises
are more thick set than dolphins. They have blunt noses. They mainly hunt
for fish like herrings. The common porpoise usually stays in the northern
seas and rivers. Dolphins
are very intelligent. This streak of intelligence becomes apparent right
from the day they are born. Baby dolphins are born tail first. As soon as
the baby dolphin is born, the mother, or attendant whales, guide it to the
surface for it to take its first breath. After that, the baby can swim and
breathe without help.
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Dolphin |
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Although
dolphins have no vocal chords, they can communicate with each other, navigate and hunt for prey by making distinctive underwater
sounds. The dolphin can make as many as thirty-two varieties of sounds
including whistles, groans, barks, clicks and squeals. For the purpose of
navigation and hunting, they use the echolocation technique that the bats
did. When lost, dolphins can find their way back by using the same echolocation technique.
Researchers
have made a thorough study of dolphins in captivity. Dolphins have also
been bred successfully in captivity.
A
dolphin’s enemy is the shark. The saving grace for the shark is that a
dolphin will never eat a shark, although sharks may eat dolphins. Often,
it is the shark that preys on solitary dolphins. But when in schools,
dolphins are capable of attacking, outwitting and injuring the shark
fatally. It is said that that in one instance, it happened in the USA, a
group of dolphins had been sharing a large tank peacefully with a shark.
However, when the shark was about to give birth, the dolphins decided they
had had enough. They lined up at the far end of the tank from the shark
and then began racing through the water towards the shark, one at a time.
Each dolphin would race to the shark and smash its beak into the shark’s
side. Within a few minutes of the attack, the shark died. Why the dolphins
did what they did, has remained a mystery.
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