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| Whale |
All whales, dolphins and porpoises, belong to the scientific order Cetacea. In spite of sharing many common traits, whales are not fish but mammals. They are warm-blooded animals, they breathe air through their lungs, they give birth to live young and they nurse them. More than 80 species make up the Order Cetacea, which are classified into two suborders: the Mysticetes (the baleen whales) have baleen in their mouths and have two blowholes; the Odontocetes (the toothed whales, dolphins and porpoises) have teeth and a single blowhole. Their size and forms are variable. Whales lack hind limbs, the forelimbs have evolved into flippers, and the whale's tail (made of cartilage) is positioned horizontally, unlike a fish’s vertical tail, enabling the whale to swim through the water by moving it up and down and displacing water.
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| Blue Whale |
The whales live in all oceans. Many of them migrate, meaning they travel throughout the year between the territories where they feed in the summer and where they reproduce in the winter. Most whales feed in cold, polar waters rich in krill or other food sources. There they spend 4 to 6 months eating, accumulating an excess of blubber, or fat, which serves as a food reserve used during the breeding season in warmer waters, where food is often scarce.
The toothed whales, which include the dolphins, porpoises, orcas and the sperm whale, feed on fish and squid. They do not use their teeth to chew, only to capture and tear their food. The baleen whales, including the right, blue and humpback whale, do not have teeth but baleen: a row of plates that hang like a curtain from both sides of the upper jaw. They feed on plankton, particularly on krill (tiny crustaceans similar to shrimp) or on small fish. The internal edge of each baleen plate is frayed, forming a sort of net or filter. The whales allow the water to enter their mouths and drain out again with their mouths open, or they use the pressure of their tongues to force the water back out of the baleen plates, which act as a filter in retaining the food left in the mouth after the water is expelled.
Like all mammals, whales have lungs. They must come to the surface periodically to breathe, as they cannot breathe under water. They take in air through their blowhole, essentially their nostrils, located on top of the whale’s head; this allows them to breathe without lifting their heads out of the water. The baleen whales have two blowhole openings and toothed whales only one. When a whale dives, the blowhole stays closed. When coming to the surface to breathe, the whale exhales the air in its lungs with great force, and moisture from the exhalation forms a large vapor cloud, known as the whale's “blow” or “ spout”. All the whales are great swimmers and divers. They are able to hold their breath for extended periods of time; the sperm whale is the dive champion, able to hold its breath for up to two hours at a time, and dive to depths as great as two miles.
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| Grey Whale |
You can’t see a whale for the first time and not remember it for the rest of your life. Roger Payne, President of the Ocean Alliance The Cetaceans have been on the Earth for approximately 50 million years, a length of time difficult to imagine. Today, many of them are in danger of extinction. To understand why, we must look at many of our own activities that affect the health of the planet,especially the oceans.
