Balaenoptera Musculus, or the blue whale, is the largest mammal in the world. This enormous mammal can grow to be 110 feet long and weigh as much as 190 tons. That’s longer than two city buses and the total weight of 30 elephants. This giant is powered by a heart the size of a taxi-cab. The blue whale’s of the Antarctic grow larger than those of the Northern Hemisphere. Also, the females tend to be slightly larger than the males of the same age.
These mammals are bluish-gray in color, with some paler spots. Algae tends to accumulate on their bellies causing a yellowish or mustard color. It has a mottled appearance with a broad, flattened U-shaped head. Fifty to ninety throat grooves run from the mouth to the belly. Instead of teeth, blue whales have 270 to 400 black baleen plates on each side of their mouths. These plates are about forty inches long and twenty-two inches wide.
The blue whale has a tiny, stubby dorsal fin set far back on its body. It has a 20 foot wide, slightly notched, triangular flukes, which is propelled by an extremely thick tail stock. The flippers on this creature are long and slender, and are about one-seventh of the whale’s body length. The blue whale’s most prominent feature is its exceptionally fleshy splashgaurd, which surrounds the blowholes at the front and sides. This whale spouts a single slender jet that soars forty to fifty feet high.
The blue whale has very poor eyesight, no sense of smell, and has no sense of taste. However, the blue whale does have well-developed senses of touch and hearing. This large mammal has a life span of about eighty years.At this time there is not too much known about the blue whale’s behavior. Blowing and diving patterns vary according to the whale’s activity.
The blue whale blows every ten to twenty seconds for a total of two to six minutes, when relaxed, and then dives. They usually stay submerged for five to twenty minutes, but can stay under for up to 40 minutes. Blue whale’s usually dive to around 490 feet, but can go deeper if need be. When swimming slowly, the whale rises at a shallow angle. He blows as soon as the head begins to brake the surface. The head disappears below the surface and a long expanse of the back rolls into view. The dorsal fin normally appears some time after the blow has dispersed and the head has disappeared. The dorsal fin is visible only briefly before the whale arches its back in preparation for the dive.
Sometimes the whale arches its tail stock, but often simply sinks below the surface.The blue whale can accelerate to speeds of over 19 miles per hour when it is being chased, but usually he swims much slower. Adult whales rarely, if ever, breach clear of the water. Youngsters, however, have been observed breaching at an angle of 45 degrees, and landing on their stomachs or sides.Blue whales are close knit and are usually found in groups of 1-5. You may see up to 30 whales gathered at the feeding grounds.
Most feeding seems to take place during the evening and early morning. The whales produce ultrasonic chirps and whistles when feeding. They use a low frequency moan to call to each other.This mammal uses its powerful muscles in the tail to drive the great fan-shaped blades (flukes) up and down to propel itself through the water. It takes him very little energy to swim. Their bodies are designed better than man-made missiles or submarines. They have a fine oil that lubricates their smooth, thin skin and reduces friction.
Blue whales have extremely flexible and marvelously streamlined bodies that help them glide through the water without a ripple. Their bones are light and spongy, making them naturally buoyant. They neither rise nor sink, but can stay at any given depth without any effort. Dorsal fins and flippers give the whale stability and keep them right side up. The flippers rotate at the shoulders and are used for steering and braking.Blue whales descend from early land mammals. Millions of years ago the richness of life in the sea lured them to water.
Aquatic life gradually changed their physical characteristics. Today, they spend most of their time in the Arctic and Antarctic Oceans, where the plankton is plentiful. In winter, the whales migrate to the warm waters of the tropics. Food in the tropics is scarce, so the whales depend on their thick layer of blubber for nourishment.
They migrate to the polar regions in the spring, and move to open seas in the fall to spend winter.The blue whale is patchily distributed worldwide, mainly in the cold waters and the open seas. There are three main populations of blue whales.They’re located in the North Atlantic, North Pacific, and the Southern Hemisphere.
Most of the whales live in the southern hemisphere, but are often found in the Gulf of California, the Gulf of Lawrence, in Canada, and the Northern Indian Ocean.Blue whales feed exclusively on krill and zooplankton. The eat about eight tons of krill a day. The whale gulps its food in great mouthfuls of sea soup. The mouth and baleen work together as a strainer, holding as much as five tons of water and krill with each mouthful. The throat grooves expand and contract to hold this vast amount of sea soup. The whale forces the water out through the baleen, which traps the krill in the baleen bristles. He then uses his fleshy tongue to lick the krill off the bristles.
His stomach can hold up to nine tons of food. The mammal is at the top of the ocean food chain but sometimes, if sick or injured, the are attacked by killer whales.Mating occurs in the summer, in the warm waters of the tropics. Sometimes ship radio signals interfere with the mating calls of the whales. The blue whale sexually matures at ten years of age. The blue whale, like other mammals, gives birth to live young.
The gestation period lasts for 11 months. The mother gives birth to a single calf, rarely twins, every two years. Other females help deliver the calf and nudge the newborn to the surface for its first breath of air. The calf is 24 feet long and weighs tow tons at birth. The calf is nursed for about one year.
It drinks more than 160 gallons of milk per day. In its first year the calf gains nine kilograms per day. The mother whale is highly protective of her baby and stays close to it for the first year of its life.The only predator of the huge blue whale is man. Population figures for the world’s largest creature differ, but the endangered animal appears to be inching away from extinction. When the commercial whaling of the blue whale was banned in 1966, the species was close to being wiped out.Whalers hunted the whales for their blubber. The blubber was boiled to remove the whale oil.
The oil was than used in soap, tallow, glycerin, edible fats, machine oil, and fine grease. It was also used for tanning, waterproofing, chamois leather, and paint oils. The whale meat was eaten in the Mediterranean and the Far East. They also extracted glue and gelatin from the tissues, Vitamin A from the liver, insulin from the pancreas, and ACTH from the pituitary gland. The whales giant lower jawbone was used as an arch to support the roof of homes for the Eskimos and other hunters.
Bones and teeth provided materials for their weapons, tools, and household utensils.For the next century, whalers vigorously pursued the blue whale and depleted its populations, first in the North Atlantic, then the North Pacific, and finally in its region of greatest abundance, the southern oceans. There perhaps 190,000 blue whales once roamed. The hunt reached its peak in the Antarctic summer of 1931 with the killing of 29,400 blue whales. Never again were whalers able to find so many blue whales to kill.The movement to save the world’s whales began more than 30 years ago when scientists began to understand whale behavior. Biologists believe that the blue whale is finally on the rebound, in at least one corner of the world’s oceans. During a 1991 ship survey off the coast of California, it was reported that there was a dramatic increase in the number of blue whales.
They believe that there are more than 2,050 blue whales feeding in the Pacific Ocean off California alone. This is up from the 1974 estimate of 1600 blue whales. Scientists assume that the population of blues now feeding off California migrates south to warmer waters off Baja or Mexico, during winter. The blue whale was listed as endangered as soon as the U.S. Endangered Species Act took effect in 1973.
Since the blue whale deadly encounters with whalers ended, blues have seldom crossed paths with humans. Direct and indirect interactions with humans are believed to be hindering recovery of the whale population. Among them are collisions with ships, entanglements in fishing gear, oil spills, pollution, coastal development, and human generated noise in the oceans.
Yet the blue whale is increasing in visibility and in numbers off the California coast. There seems to be little good news about blue whales coming from the rest of the world’s oceans. California waters may now represent some of the most critical large whale habitats in the world.Bibliography:Bibliograpghy1.
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