Blue Whale

(Jrt)

Blue Whale
The blue whale (or "Blue Fin whale") is one of the largest animals that ever lived on earth (20 to 34 meters and 100 to 190 tons). The largest specimen ever seen measured 35 meters long and weighed 200 tons (gestation); his tongue weighed 4.3 tons and its heart 698.5 kg.

Only dinosaurs have approached its size.

It is a species now considered threatened, which has greatly decreased since a century because of the intensive hunt that has been made to the whales. Within baleen whales, or mysticètes, the blue whale is the longest.

Lifestyle
She lives in warm waters and tropical breeding season (she gives birth to a single small by nearly 7 meters long and 3 tons). But she emigrated to regularly water cooler across almost the entire planet.

It feeds primarily on krill like many other whales. She also enjoys plankton (small shrimp that move in shoals) and crustaceans, but does not reject small fish (like sardines).

His mouth contains baleen effective allowing the whale to swallow thousands of gallons of sea water and food. The baleen are - more precisely - long plates (one meter long) ending with long thick hair. This complex filter plankton may withhold several tons of water in one sip. The whale then uses his tongue to get food and collected.

Singing whales
It was estimated between 200 000 and 300 000 the number of blue whales in the early twentieth century. During one hunting season in 1930, there were 30 000 blue whales killed in Antarctica. The restrictions, as drastic as they are, have certainly been taken too late and it is not certain that these whales were saved from extinction. The Southern populations are estimated at less than 5 000 individuals, but it does not rest probably more than 2000 individuals living in 3000.

Systematique

─ o Balaenopteridae and Eschrichtiidae
├ ─ o
│ ├ ─ o
│ │ ├ ─ o Balaenoptera musculus
│ │ ├ ─ o Megaptera novaeangliae
│ │ └ ─ o Eschrichtius robustus
│ └ ─ o
│ ├ ─ o B. physalus
│ └ ─ o
│ ├ ─ o B. edeni
│ └ ─ o
│ ├ ─ o B. Borealis
│ └ ─ o B. brydei
└ ─ o
├ ─ o B. bonaerensis
└ ─ o B. acutorostra


Read also Dauphin

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