lukes up and down.Another characteristic that is helpful to killer whales, or any type of whale, is that a whale's backbone, ribcage, and shoulder blades resemble those of other mammals. Almost all mammals have seven neck vertebrae. In killer whales, these vertebrae are compressed into a short length or joined together into one bone. This keeps the head from moving about. It also joins the head directly to the body. Orcas have smooth, rubbery skin that easily slips through the water. Mammals have hair to keep them warm. Whales have only a few hairs on the head. To keep warm, they have a layer of fat called blubber. The blubber grows to about 6 inches thick never growing more. If there is no food around or there is little food, killer whales can live off their blubber for a long time. Since blubber is lighter than water, this increases the buoyancy of whales.Much like their mammal brethren, whales have lungs and must come to the surface to breathe. They can hold their breath for long periods of time. Their muscles store more oxygen than the muscles of other mammals. Orcas store 41 percent of their oxygen supply in the muscles. When diving, the body reduces the blood flow to the muscles, still keeping a normal flow to the heart and brain. The heartbeat slows helping to save oxygen. After a dive, a killer whale must take several breaths to recharge its tissues with oxygen before diving again. When an orca comes up to breathe, it rolls forward as it breaks the surface. This movement gives it only about two seconds to blow out and breathe in up to 2,100 quarts of air. They breathe through nostrils called blowholes. These are located at the top of the head. Orcas have one blowhole. Powerful muscles and valves open the blowhole wide so the whales can breathe. Then they snap tightly shut. A cloud called a blow or spout is produced when a whale exhales. It consists of water vapor. Sometimes it may include mucus and oil ...
