Blue Whale Status: Endangered
The world's largest mammal
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Subclass: Eutheria Order: Cetacea Suborder: Mysticeti Family: Balaenoptiidae Genus: Balaenoptera Species: musculus
Binomial name
Balaenoptera musculus Linneaus , 1758
Blue Whale range

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.

Contents

1 Taxonomy 2 Size 3 Population and whaling 4 References 5 External links

Taxonomy

The Blue Whale is one of seven species of whale in the genus Balaenoptera. It is divided into three subspecies: B. m. musculus, the north Atlantic and north Pacific populations, B. m. intermedia, the Southern Ocean population and B. m. brevicauda which is a small whale also known as the Pygmy Blue Whale.

The specific name musculus is the Latin for muscle or mouse.

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 a 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 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.

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.

External links

• Blue Whale photographs by Mike Johnson, Marine Natural History Photographer
• American Cetacean Society Blue Whale fact sheet
• Information on Blue Whales from EnchantedLearning.com
• Numerous Blue Whale photographs from OceanLight.com