Kingdom: Animalia... Phylum: Chordata... Class: Mammalia... Order: Cetacea... Family: leer texto...

Some species of large whales are endangered as a result of large-scale whaling during the nineteenth and twentieth centuries. For centuries large whales have been hunted for oil, meat, baleen and ambergris (a perfume ingredient from the intestine of sperm whales). By the middle of the 20th century, whaling left many populations severely depleted.
The International Whaling Commission introduced a six year moratorium on all commercial whaling in 1986, which has been extended to the present day. For various reasons some exceptions to this moratorium exist; current whaling nations are Norway, Iceland and Japan and the aboriginal communities of Siberia, Alaska and northern Canada.  Whales are also threatened by climate change and global warming. As the Antarctic Ocean warms, krill populations, that are the main food source of some species of whales, reduce dramatically, being replaced by jelly like salps.



Whales are cetaceans. All cetaceans, including whales, dolphins and porpoises, are descendants of land-living mammals of the Artiodactyl order (even-toed ungulate animals). Orcas (Killer Whales) and Pilot whales have "whale" in their name, but they are dolphins for the purpose of classification. The term whale is also sometimes used to refer to all cetaceans or just larger cetaceans.
Both cetaceans and artiodactyl are now classified under the super-order Cetartiodactyla which includes both whales and hippos. In fact, whales are the closest living relatives of hippos; they evolved from a common ancestor at around 54 million years ago. Whales entered the water roughly 50 million years ago.
Cetaceans are divided into two suborders:
-The baleen whales are characterized by baleen, a sieve-like structure in the upper jaw made of keratin, which they use to filter plankton from the water. They are the largest species of whale.
-The toothed whales have teeth and prey on fish, squid, or both. An outstanding ability of this group is to sense their surrounding environment through echolocation.



The Blue Whale is the largest known mammal that has ever lived, and the largest living animal, at up to 35 m (105ft) long and 150 tons.
Whales generally live for 30-90 years, depending on their species, and on rare occasions can be found to live over a century. Recently a fragment of a lance used by commercial whalers in the 19th century has been found in a bowhead whale caught off Alaska, which showed the whale to be between 115 and 130 years old. Furthermore, a technique for dating age from aspartic acid racemization in the whale eye, combined with a harpoon fragment, indicates an age of 211 years for one male, making bowhead whales the longest lived extant mammal species.

Whales are warm-blooded, feed their young milk from mammary glands, and have some very little hair. Like all mammals, whales breathe air into lungs. The body is quite resembling the form of a fish. The end of the tail holds the fluke aka tail fins, which provide propulsion by vertical movement.
The forelimbs are called flippers. Although whales generally do not possess hind limbs, some whales sometimes have rudimentary hind limbs; some even with feet and digits. Most species of whale bear a fin on their backs known as a dorsal fin. Whales have a four-chambered heart. Under the skin lies a layer of fat, the blubber. It serves as an energy reservoir and also as insulation. The neck vertebrae are fused in most whales, which provides stability during swimming at the expense of flexibility. They have a pelvis bone, which is a vestigial structure.

Whales can breathe through their blowholes, it is located on the top of the head so the animal can remain submerged. Baleen whales have two blowholes, while the toothed whales have only one. The shapes of whales' spouts when exhaling after a dive, differ between species. Whales have a unique respiratory system that lets them stay underwater for long periods of time without taking in oxygen. The Sperm Whale, can stay underwater for up to two hours!… With a single breath of course.

Whales are widely classed as predators, but their food ranges from microscopic plankton to very large fish. Males are called bulls; females, cows. The young are called calves. Females give birth to a single calf. Nursing time is 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, in ost cases from seven to ten years of age. This mode of reproduction spawns few offspring, but in return, it gives a better probability of survival. At birth newborn are delivered tail-first, minimising the risk of drowning. Whale cows nurse by actively squirting milk the consistency of toothpaste into the mouths of their young preventing loss to the surrounding aquatic environment.

Because of their environment, whales are conscious breathers: they decide when to breathe. All mammals sleep, including whales, but they cannot afford to fall into an unconscious state for too long, since they need to be conscious in order to breathe. Whales also communicate with each other using lyrical sounds, called whale song. They have been known to generate about 20,000 acoustic watts of sound at 163 decibels. Being so large and powerful, these sounds are also extremely loud and can be heard for many miles.

The Whale is a mammal

whale skeleton




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Some Whales, can stay underwater for up to two hours!


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