Like all mammals, whales breathe air into the lungs, are warm-blooded, feed their young with milk mammary glands, and some (albeit very little) to the hair.
The body is fusiform, reminiscent of the streamlined form of fish. The forelimbs, also called flippers are shaped paddles. At the end of the tail has a fluke, or tail fins, which provides propulsion by the vertical movement. Although the whales generally do not have rear limbs, some whales (such as sperm whales and baleen whales) sometimes have the basic rear limbs, some even with the legs and numbers. Most fin whale species bear their backs known as the dorsal fin.
Under the skin is a layer of fat, blubber. It serves as a reservoir of energy, as well as insulation. Wales has four chambered heart. Karku vertebrae are fused in most whales, which provides stability when operating at the expense of flexibility. They have the bones of the pelvis, which is a vestigial structure.
Whales breathe through their blowholes, located in the upper part of the head, so the animal can remain submerged. Baleen whales have two; whales have teeth. The shapes of whales' spouts when exhaling after the dive, when seen from the point of view of the law, differ between species. Wales has a unique respiratory system, which lets them stay underwater for long periods of time without taking in oxygen. Some whales, such as the Sperm whale, stay underwater for two hours holding a single breath. The Blue Whale is the largest known mammal that ever lived, and most live animals, amounting to 35 metres (105ft) long and 150 tons.
Whales generally live for 30-90 years [also] depending on their species, and on rare cases can be found to live more than a century. Recently, a fragment of the lance used by commercial Whalers in the 19 century has been found in the bowhead whale caught off Alaska, which showed the whale is between 115 and 130 years of life. In addition, techniques dating from the age of aspartic acid racemization eye on the whale, in conjunction with the harpoon fragment indicates, age 211 years for one male, which bowhead whales lived the longest existing species of mammals.
Whale flukes can often be used as identifying markings, as is the case for humpback whales. It is a method by which the publication errant Humphrey the whale has been identified in three separate observations.