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More About Whales ...
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Whales are the largest species of exclusively aquatic placental mammals, members of the order Cetacea, which also includes dolphins and porpoises. The term whale is ambiguous: it can refer to all cetaceans, just the largest ones, or only to members of particular families within the order Cetacea. This latter definition is the one followed within Wikipedia. Whales are those cetaceans which are neither dolphins (i.e. members of the families Delphinidae or Platanistoidae) or porpoises. This can lead to some confusion as Orca (Killer Whales) and Pilot Whales have "whale" in their name, but are dolphins from the perspective of classification. Cetologists tend not to worry too much about making a distinction.
Like all members of the order, whales evolved from land mammals which returned to the sea undergoing aquatic adaptation, probably in the Eocene, between 55 and 34 million years ago. The precise ancestry of whales is still obscure, as there is no commonly agreed succession, but they are thought to have evolved from a group of carnivorous artiodactyla (even-toed hoofed animals). In 2001, two important 47-million-year-old partial fossils, named Rodhocetus balochistanensis and Artiocetus clavis, were discovered in Balochistan, Pakistan. These fossils represent intermediate forms between land-living ungulates and whales and are evidence that the whales' closest relatives on land might be hippos, which had been previously suggested by DNA studies. The first fully marine cetaceans, like Basilosaurus, appeared 40 million years ago.
Like all mammals, whales breathe air into lungs, are warm-blooded (i.e., endothermic), breast-feed their young, and have some (very little) hair. The whales' adaptions to a fully aquatic life are quite conspiciuous: The body is fusiform, resembling that of a fish. The forelimbs, also called flippers, are paddle-shaped. The end of the tail holds the fluke, which provides propulsion by vertical movements. Whales do not possess hind limbs, small bones inside the body are the only remains of the pelvis. Most species of whales bear a fin on their backs. Beneath the skin lies a layer of fat, the blubber. It serves as an energy reservoir and also as insulation. Whales have a four-chambered heart. The neck vertebrae are fused in most whales, whhich provides stability during swimming at the expense of flexibility. Whales breathe through blowholes, located on the top of the head so the animal can remain submerged. Baleen whales have two, toothed whales one blowhole. When breathing out after a dive, a spout can be seen from the right perspective, the shape of which differs among the species. Whales have a unique respiratory system that lets them stay underwater for long periods of time without taking any oxygen. Some whales, such as the Sperm Whale, can stay underwater for up to two hours in a single breath.
Whale females give birth to a single calf. Nursing time is long (more than one year in many species), which is associated with a strong bond between mother and young. In most whales reproductive maturity occurs late, typically at seven to ten years. This strategy of reproduction spawns few offspring, provided with a high rate of survival
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Source: Wikipedia Read more about Whales
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INFO LINKS
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Southern right whale
BBC Nature: Wildfacts
Southern right whale: Facts and Pictures Read More
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Sowerby's beaked whale
BBC Nature: Wildfacts
Sowerby's beaked whale: Facts and Pictures Read More
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Stejneger's beaked whale
BBC Nature: Wildfacts
Stejneger's beaked whale: Facts and Pictures Read More
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Strap-toothed whale
BBC Nature: Wildfacts
Strap-toothed whale: Facts and Pictures Read More
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True's beaked whale
BBC Nature: Wildfacts
True's beaked whale: Facts and Pictures Read More
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Beluga Whale
BBC Nature: Wildfacts
Beluga Whale: Facts and Pictures Read More
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Bowhead Whale
BBC Nature: Wildfacts
Bowhead Whale: Facts and Pictures Read More
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Gray Whale
U.S. Fish and Wildlife Service
Endangered species report for Gray Whale Read More
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Southern Right Whale
MarineBio.com
Southern Right Whale: facts, pictures, habitat, and other information Read More
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Bryde's Whale
MarineBio.com
Bryde's Whale: facts, pictures, habitat, and other information Read More
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Humpback Whale
MarineBio.com
Humpback Whale: facts, pictures, habitat, and other information Read More
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Fin Whale
MarineBio.com
Fin Whale: facts, pictures, habitat, and other information Read More
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Blue Whale
MarineBio.com
Blue Whale: facts, pictures, habitat, and other information Read More
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Sperm Whale
Oceanic Research Group
Lesson plans with narrative and pictures Read More
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Beluga Whale
National Geographic
Beluga Whale fact sheet and pictures; video clip; audio clip Read More
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Blue Whale
National Geographic
Blue Whale fact sheet and pictures; video clip; audio clip Read More
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Gray Whale
National Geographic
Gray Whale fact sheet and pictures; video clip; audio clip Read More
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Humpback Whale
National Geographic
Humpback Whale fact sheet and pictures; video clip; audio clip Read More
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Killer Whale
National Geographic
Killer Whale fact sheet and pictures; audio clip Read More
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Narwhal
National Geographic
Narwhal fact sheet and pictures; video clip; audio clip Read More
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Right Whale
National Geographic
Right Whale fact sheet and pictures; video clip; audio clip Read More
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Sperm Whale
National Geographic
Sperm Whale fact sheet and pictures; video clip; audio clip Read More
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Belouga
Oceanes - the holiday designer
Brief description and categorized information about Belouga Read More
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Blue whale
Oceanes - the holiday designer
Brief description and categorized information about Blue whale Read More
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Fin whale
Oceanes - the holiday designer
Brief description and categorized information about Fin whale Read More
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Grey whale
Oceanes - the holiday designer
Brief description and categorized information about Grey whale Read More
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Humpback whale
Oceanes - the holiday designer
Brief description and categorized information about Humpback whale Read More
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Mink whale
Oceanes - the holiday designer
Brief description and categorized information about Mink whale Read More
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Northern right whale
Oceanes - the holiday designer
Brief description and categorized information about Northern right whale Read More
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Southern right whale
Oceanes - the holiday designer
Brief description and categorized information about Southern right whale Read More
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Sperm whale
Oceanes - the holiday designer
Brief description and categorized information about Sperm whale Read More
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Unicorn whale
Oceanes - the holiday designer
Brief description and categorized information about Unicorn whale Read More
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Southern Right Whale
Unique Australian Animals
Categorized information on Southern Right Whale including description, habitat, feeding, etc. Has nice pictures, too. Read More
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Humpback Whale
National Wildlife Federation
Categorized information about Humpback Whale Read More
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Grey Whale
bcadventure.com
Brief description of Grey Whale Read More
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Humpback Whale
bcadventure.com
Brief description of Humpback Whale Read More
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