Still, whales need a source of insulation as many of them travel through or live in icy cold ocean waters. For this, they have a layer of blubber, or fat, just under the surface of their skin. This layer of blubber does not only insulate the whale’s body to conserve heat, but provides energy to the animal as it migrates across extensive waters and provides buoyancy as it is less dense than water.
Whales have a skeleton of bone and cartilage. The bone provides stability and strength, while the cartilage gives these large bodies flexibility and makes them a little lighter than if the skeleton was made completely from bone. Each flipper has finger-like bones, gives them dexterity and support. The tail (or fluke) of the whale is not at all supported by bones, as it needs to be as flexible as possible in order to propel the animal.
One of the best-known characteristics of whales is their blowhole. Whales breathe by means of lungs, and not gills (like fish). The blowhole is situated on top of the head and is used to inhale and exhale through. The shapes of the spouts created by various whales are used to determine the species by experienced whale watchers.
The whale’s body is streamlined in a fusiform shape. This means that it is tapered in the front and back to allow it to glide easily through the water. The strong fluke (or tail) moves up and down powerfully to propel the whale through the water with a consistent force (unlike fish that need to dart here and there and then travel rather slowly at other times). Most whale species have dorsal fins (on the upper part of their bodies). The pectoral fins (on the underside), when present, are designed to steer the animal rather than to propel it as they are small and not very strong. The body is fairly rigid, not being used much to move the animal forward.
The genitals of both male and female whales are concealed, with genital slits on the undersides leading to these organs. In fact, the male’s testes are concealed within the abdomen, and can only be found when the whale has been opened surgically and its intestines moved or removed. The testes of the Sperm Whale can weigh up to 100 pounds or more than 45 kilograms.
Baleen whales do not possess teeth, but have massive sieve-like structures in their mouths. These filter huge mouthfuls of sea water, extracting the plankton and tiny fish out of it, which the whale then eats. The plates have a straight outer edge and are quite a bit broader at the top than at the bottom. The thickness and elasticity of the hairs of the baleen plates vary from one species to the next. Toothed whales are hunters, and use their teeth to grasp and tear at their prey. The number and structure of these teeth differ from species to species. However, the teeth are not used extensively, even in species in which they are quite well developed. Frequently, these teeth are found to be covered in barnacles, indicating that they have not been used for quite some time.
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