The Blue Whale (Balaenoptera musculus) is a mammal which belongs to
the baleen whales suborder. They are filter-feeders, using their baleen to
strain plankton out of the seawater. The Blue Whale is the largest animal known to
have ever lived, at up to 30 meters in length and 150 tons or more in weight.
The blue whale has a tiny dorsal fin, visible only briefly during the dive sequence. It has a spectacular 9 m vertical
single column blow. Its lung capacity is 5,000 litres.
Blue whales can reach speeds of 30 mph (50 km/h), but 12 mph (20 km/h) is more typical.
Taxonomy
The Blue Whale is one of seven species of whale in the genus Balaenoptera. The species has been classified into three
subspecies: B. m. musculus, consisting of the north Atlantic and north Pacific populations, B. m. intermedia, the
Southern Ocean population and B. m. brevicauda (also known as the Pygmy Blue Whale) found in the Indian Ocean and
South Pacific. This subdivision into three subspecies is still questioned by some scientists; genetic analysis may yet show there
are just two true subspecies.
The specific name musculus is Latin and could mean
"muscular", but it can also be interpreted as "little mouse." Linnaeus would have known this and, given his sense of humor, may have intended the ironic double
meaning.
Size
The Blue Whale is believed to be the largest animal ever to have lived on Earth. The largest creature known from the dinosaur era is the Brachiosaurus
of the Mesozoic, which is estimated to have weighed up to 80 tons. There is some
uncertainty as to the biggest Blue Whale ever found. Most data comes from Blue Whales killed in Antarctic waters during the first half of the twentieth century and was collected by whalers not well-versed in standard zoological measurement techniques. The longest whales ever recorded were
two females measuring 33.6 m and 33.3 m respectively. There are some disputes over the reliability of these
measurements, however; the longest whale measured by scientists at the American
National Marine Mammal Laboratory (NMML) was 29.9 m long—about the same length
as a Boeing 737 aeroplane.
A Blue Whale's head is so wide that 50 people would be able to stand on its tongue. Its heart is close to the size of a small
car. A human baby could crawl through a Blue Whale's arteries. A newborn Blue Whale calf weighs more than an adult elephant and
is 25 feet (7.6 metres) long. During the first 7 months of its life, a baby Blue Whale drinks approximately 100 US gallons (379
litres) of milk every day. Baby Blue Whales also gain weight fast: 200 pounds (91 kg) every 24 hours.
Blue Whales are very difficult to weigh on account of their massive size. Most Blue Whales killed by whalers were not weighed
as a whole but cut up into manageable pieces before being weighed. This caused an underestimate of the total weight of the whale
due to loss of blood and other fluids. Even so, measurements between 160 and 190 tons were recorded of animals up to 27 m in
length. The weight of a 30 m individual is believed by the NMML to be in excess of 200 tons. The largest blue whale to date
is a female that weighed 389,760 pounds (176,792 kg).
Population and whaling
Blue Whales are not easy to catch, kill and retain. Their speed and power meant that they were not often the target of early
whalers who instead targeted Sperm and Right Whales. As the number of these species declined, whalers eyed the meaty prize of the largest baleen
whales, including the Blue Whale. In 1864 Norwegian Svend Foyn equipped a steam-powered
boat with harpoons specifically designed for catching large whales. Although
initially troublesome, the method caught on, and by the end of the nineteenth century stocks of Blue Whale in the North Atlantic
had diminished.
Killing of Blue Whales spread rapidly across the oceans and by 1925, the United States, Britain
and Japan had joined Norway in chasing whales
on 'catcher boats' that caught the whales and handed them onto huge 'factory ships' for processing. In 1930, forty-one ships killed 28,325 Blue Whales. By the end of World War II populations had rapidly depleted and in 1946 the first
quotas restricting international trade in whales were introduced. These were ineffective because of the lack of differentiation
between species. Rare species could be hunted equally with those found in relative abundance. By the time Blue Whale hunting was
finally banned in the 1960s by the International Whaling Commission, 350,000 individuals had been killed. The total
world population is now 3–4,000 with the largest concentration of 2,000 individuals located off the coast of California. This group represents the best hope for a long-term recovery in Blue Whale
population. The Blue Whale has been on the list of endangered species since the 1960s. In Chile, the Cetacean Conservation Center
- CCC-Chile, www.ccc-chile.org - is undertaking extensive research and conservation work on a recently discovered feeding
aggregation of the species off the coast of Chiloe Island, with support from the Chilean Navy.
References
- Blue Whales, John Calambokidis and Gretchen Steiger. ISBN 1900455218
- Randall R. Reeves, Brent S. Stewart, Phillip J. Clapham and James A. Powell (2002). National Audubon Society Guide to
Marine Mammals of the World. Alfred A. Knopf, Inc. ISBN 0375411410.
- American Cetacean Society. Blue Whale (http://www.acsonline.org/factpack/bluewhl.htm). Retrieved Jan. 7, 2005.
External links
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