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The Life on the Sea | ||
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Orcas: Killer Beauties
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The Life on the Sea | ||
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Swimming.
The speed and the duration of swimming are very united: Swimming at high speeds probably last a few seconds, while swimming at lower speeds, can last indefinitely. Orcas are the fastest marine mammals in the world.
They reach speeds of up to 30 miles per hour or 48,4 kilometers per hour, but the usually preferred speed oscillates between the 2 to 6 miles per hour or 3,2 to 9,7 kilometers per hour. They are very agile in the water; when they swim at the surface, they do just for a small time: 30 seconds or less.
Immersion.
Orcas generally lower to depths between the 100 to 200 feet (30,5 to 61 meters). The deeper immersion that was made, under experimental conditions was about 900 feet or 274,3 meters. When they submerge, they usually returns to the surface approximately every 4 or 5 minutes.
In the surface they take from two to five air inhalations in an interval of five to ten seconds before they dive again. Long immersions have been observed. The longest immersion observed in the ocean was of 12 minutes. Under experimental conditions, Orcas has submerged by 15 minutes.
All the marine mammals have special physiological adaptations, which they use during the immersion. These adaptations allow Orcas, to conserve oxygen while they are under water.
When they submerge, the blood is sent to the tissues that have greater tolerance to low oxygen levels, so that to the lungs, the heart and the brain, arrive a greater amount of oxygen. Their muscles have a great amount of a special protein that shares oxygen. This protein keeps the oxygen and prevents those muscles to suffer an oxygen deficiency.
Breathing.
The Orcas can breath by a single respiratory orifice that they have over the dorsal surface of their heads. This orifice is called "Blowhole". They stops to breathe when they are under water; and only open the blowhole before returning to the surface to exhale; In the surface, Orcas quickly inhales air and closes blowhole before starts to submerge.
When an Orca exhale, the water that has accumulated on the blowhole, is expelled with respiratory gases upwards. The sea water and the water steam, that condenses in the respiratory gases, expand in a burst of gases and water that expose the location of the Orcas, like also the real whales. There is a period in which they hold the breathing much more time that a human, and exchanges more air from the lungs with each breathing.
The Thermal Regulation.
The Orcas accumulates a greater amount of their body blubber, in a thick fat layer, that is right under the skin. This fat isolates the Orca and give form its body. Also it works like an energy reserve. Their body temperature usually is of 97,5 degrees Fahrenheit or 36,4 degrees Celsius, However there's a heat dispersion system that transfers heat from the blubber to animal's skin.
The circulatory system of the Orcas is designed to conserve, dissipate and to maintain the temperature of body stable. The pectoral fin, dorsal fin and in tail flukes arteries are surrounded by veins, this way part of the heat of the blood that comes from the arteries, is transferred to the veins, that contain fresher blood. This concurrent heat interchange helps the Orcas to maintain their body temperature stable.
When an Orca dives, the blood is sent far from the surface of the skin, this diminution of circulation, conserves the body heat. If after a prolonged exercise, or if the animal is in warm waters, the Orca must then lose the excessive heat.
In this situation, the circulation of the veins near the surface of the skin is increased, in the pectoral fins, the dorsal fin and in the tail flukes and diminishes in the veins that return the fresh blood to the body. Thus the excessive heat is expelled outside the body.
The orcas fusiform body and a reduced number of extremities, reduces the amount of areas in surface of the body, that are exposed to environment. This aid the animal to conserve the body heat.
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