They fall under the category of the rorquals, which arethe largest of the baleen family. The scientific name of the Blue whale is,Balsenoptera musculus. Key Words: Balaenoptera musculus, Suborder Mysticeti,balaenoptera intermedia, balaenoptera brevicauds, baleen whale, rorqual, calf,sulfur bottom, Sibbald’s Rorqual, Great Northern Rorqual, gulpers, blowholes,blubber, oil, keratin, krill, copepods, plankton, orcas, endangered IntroductionWhales are separated into two groups, the baleen and the toothed whales. Theblue whale is the largest baleen whale and the largest animal that ever lived onEarth, including the largest dinosaurs. Baleen are rows of coarse, bristle-likefibers used to strain plankton from the water.
Baleen is made of keratin, thesame material as our fingernails. They live in pods, the have two blowholes. Theblue whale has a 2-14 inch (5-30cm) thick layer of blubber. Blue whales (Balaenopteramusculus) are baleen whales (Suborder Mysticeti). They are one of 76 species andare marine mammals. Background The Blue whale is called a “rorqual”, aNorwegian word for “furrow” referring to the pleated grooves running fromits chin to its naval.
The pleated throat grooves allow the Blue whale’sthroat to expand during the huge intake of water during filter feeding; they can”hold 1,000 tons or more of food and water when fully expanded” (Small1971). Blue whales have 50-70 throat grooves. Blue whales grow up to about 80feet (25m) long on average, weighing about 120 tons. The females are generallylarger than the males, this is the case for all baleen whales.
“The largestspecimen found was a female 94 feet (29m) long weighing more than 174 tons” (Satchell1998). The head of the Blue whale forms up to a quarter of the total bodylength. Compared with other rorquals, the head is very broad. The blue whaleheart is the size of a small car and can pump almost 10 tons of blood throughoutthe body. They have a very small, falcate (sickle-shaped) dorsal fin that islocated near the fluke, or tail.
Blue whales have long, thin flippers 8 feet(2. 4m) long and flukes that are 25feet (7. 6m) wide. The blue whale’s skin isusually blue-gray with white-gray spots. The underbelly has brown, yellow, orgray specks. During the winter, in cold waters, diatoms stick to the underbelly,giving it a yellow to silver- to sulfur-colored sheen; giving the blue whale itsnick-name of “sulfur bottoms”.
Other names include Sibbald’s Rorqual andGreat Northern Rorqual. Blue whales (like all baleen whales) are seasonalfeeders and carnivores that filter feed tiny crustaceans (krill, copepods, etc),plankton, and small fish from the water. Krill, or shrimp-like euphasiids are nolonger than 3 inches. It is amazing that the world’s largest animals feed onthe smallest marine life. Blue whales are gulpers, filter feeders thatalternatively swim then gulp a mouthful of plankton or fish.
“An average-sizedblue whale will eat 2,000-9,000 pounds (900-4100kg) of plankton each day duringthe summer feeding season in cold, arctic waters (120 days)” (Hasley 1984). The blue whale has twin blowholes with exceptionally large fleshy splashguardsto the front and sides. It has about 320 pairs of black baleen plates with darkgray bristles in the blue whale’s jaws. These plates can be 35-39 inches(90cm-1m) long, 21 inches (53cm) wide, and weigh 200 pounds (90kg). This is thelargest of all the rorquals, but not the largest of all the whales. The tongueweighs 4 tons.
Blue whales live individually or in very small pods (groups). They frequently swim in pairs. When the whale comes to the surface of the water,he takes a large breath of air. Then he dives back into the water, going to adepth of 350 feet (105m). Diving is also the way in which whales catch most oftheir food.
Whales can stay under water for up to two hours without coming tothe surface for more air. Blue whales breath air at the surface of the waterthrough 2 blowholes located near the top of the head. ” They breathe about 1-4times per minute at rest, and 5-12 times per minute after a deep dive” (Hasley1984). Their blow is a single stream that rises 40-50 feet (12-15m) above thesurface of the water. Blue whales are very fast swimmers; they normally swim3-20 mph, but can go up to 24-30mph in bursts when in danger.
Feeding speeds areslower, usually about 1-4mph. Blue whales emit very loud, highly structured,repetitive low-frequency sounds that can travel form many miles underwater. Theyare probably the loudest animals alive, louder than a jet engine. These songsmay be used for locating large masses of krill (tiny crustaceans taht they eat)and for communicating with other blue whales.
Blue whales typically are found inthe open ocean and live at the surface. They are found in all the oceans of theworld. The majority of Blue whales live in the Southern Hemisphere. Thesubspecies found in the Southern Hemisphere are the balaenoptera musculus. Thesmaller populations inhabit the North Atlantic and North Pacific.
These NorthernHemisphere Blue whales are the balaenoptera brevicauda. They migrate longdistances between low latitude winter mating grounds and high latitude summerfeeding grounds. They are often seen in parts of California, Gulf of California(Sea of Cortez), Gulf of St. Lawrence, Canada and the northern Indian Ocean. Blue whale breeding occurs mostly in the winter to early spring while near thesurface and in warm waters. “The gestation period is about 11-12 months andthe calf is born tail first (this is normal for cetaceans) and near the surfacein warm, shallow waters” (Hasley 1984).
The newborn instinctively swims to thesurface within 10 seconds for its first breath; it is helped by its mother,using her flippers. Within 30 minutes of its birth the baby whale can swim. Thenewborn calf is about 25 feet (7. 6m) long and weighs 6-8 tons.
Twins areextremely rare (about 1% of births); there is almost always one calf. The babyis nurtured with its mother’s fat-laden milk (it is about 40-50% fat) and isweaned in about 7-8 months. A calf may drink 50 gallons of mother’s milk andgain up to 9 pounds an hour or 200 pounds a day. The mother and calf may staytogether for a year or longer, when the calf is about 45 feet (13m) long.
Bluewhales reach maturity at 10-15 years. Blue whales have a life expectancy of35-40 years. However, there are many factors that limit the life span of theBlue whale. Packs of killer whales (orcas) have been known to attack and killyoung blue whales or calves.
Man also hunted blue whales until the InternationalWhaling Commission declared them to be a protected species in 1966 because of ahuge decrease in their population. The Blue whale was too swift and powerful forthe 19th century whalers to hunt, but with the arrival of harpoon canons, theybecame a much sought after species for their large amounts of blubber. They werealso hunted years ago for their baleen, which was used to make brushes andcorsets. But it was their size and high yield of oil that made them the targetof choice for modern commercial whalers.
Before mans intervention there were228,000 Blue whales swimming the oceans of the world. “Between 1904 and 1978,whalers scoured the seas for this huge cetacean, most were taken in the SouthernHemisphere, many illegally” (Satchell 1998). As the population figuresuggests, it was relentlessly slaughtered for every reason imaginable, almost tothe point of extinction. Another reason why Blue whales are almost extinct ispollution. Mosst of their illnesses are contracted by pollution.
It is estimatedthat there are about 10,000-14,000 blue whales world-wide. Blue whales are anendangered species. They have been protected worldwide by international law,since 1967. The blue whale was listed as endangered throughout its range on June2, 1970 under Section 7 of the Endangered Species Conservation Act of 1969. Theyare not to be hunted by anyone for any reason at all.
Suggestions are that somepopulations may never recover. Conclusion Although Blue whales are nowprotected, we still must not hunt or kill them in their delicate balance oflife. Some people believe that whales and dolphins are animal of mystery andbeauty, and that a dead whale is an omen, good or bad. Most people say that allhumans must protect all whales. We need to save these great water giants. BibliographyBerger, C.
1998 Making Sense of the Songs Whales Sing. Natural Wild Life. Volume 36, Number 8. Hasley, W. 1984. Collier’s Encyclopedia.
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Mulvaney, K. 1998. A Canny Way with Whalers. New Scientist. Volume 157, Number 2118. Satchell, M.
1998. A Whale of a Protest: Animal-RightsActivists Hope to Keep an Indian Tribe from Bringing Home the Blubber. US Newsand World Review. Volume 125, Number 13. Small, G. 1971.
The Blue Whale. NewYork Columbia University Press. New York, NY. Zimmer, C. 1998.