Blue Whale (Balaenoptera musculus)
Reference work entry
Blue Whale (Balaenoptera musculus) – a marine mammal and a rorqual of Balaenopteridae family. It is the largest existing animal and the heaviest that ever existed. It inhabits the area from the Chukchi Sea, Greenland, Spitsbergen, and Novaya Zemlya to the Antarctic. It is very rarely seen in the tropical belt. Today its population is small. Its back and sides are dark gray, with bluish shades. The body is dotted with light-gray spots and marble pattern. In the tail part, the spots are more concentrated, and tail stem is marble-like due to a great number of parasites injuring the skin. A dorsal fin is very small and located close to the tail, and its height is around 1 % from the body length. The upper jaw has 750–800 pitch-black plates up to 1 m high. The spout in the form of prolonged inverted cone is 6–9 m high. B.W. is a typical plankton eater: it feeds on small crustaceans in the upper sea layer. B.W. does not eat fish, and its stomach capacity is 1.5–2 tons crustaceans, average length is around 24 m, and average size of male and female in the Northern Hemisphere is 22.8 and 23.5 m, respectively. The maximum length of a female whale caught in the Barents Sea is 30 m weighing 135 tons. In 1909 a B.W. 33.58 m long and weighting 200 tons was measured. The tongue of the B.W. weights 4 tons. When feeding, B.W. swims 11–15 km/h, while a frightened animal can develop a speed of 33–40 km/h. However, B.W. is able to maintain such speed for only several minutes. Whales have no olfaction, their eyesight is relatively weak, but the hearing is perfect. These animals signal one another to find way and get food with the help of ultrasound. They mature at 2 years old. Female whales give birth to one calf once in 2.5 years (doubles and triples are very rare). A newborn 7-m-long calf weighs 2 tons. With the help of contraction of special muscles, a female whale injects in the calf’s mouth a very nutritious milk – it contains only 50 % of water. Whale calfs are fed on the milk during 7–8 months. One B.W. is the source of 16–20 tons of grease and 35–40 tons of eatable meat on average. In 1966 the International Whaling Commission prohibited whale catching for 5 years, later on the prohibition was prolonged for indefinite term. In the nineteenth century, B.W. was usual in waters near the Kola Peninsula and Novaya Zemlya, and today they are never seen there. B.W. live alone or in small groups. At present it inhabits the following regions: the northern part of the Bering Sea, the waters of the coasts of Peru and Chile, and the Grand Banks. B.W. is listed in the Red Book.
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