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beluga
The Beluga (Delphinapterus leucas) is a sea mammal belonging to the whale family. Belugas live in icy shallow waters of the arctic and subarctic oceans. They are well adapted to the life close to the ice packs.
The absence of a dorsal fin allows whales to swim close to the ice surface in order to locate breathing holes. These essential holes are partially located by eye but mostly with help of their echolote system. The obligate clicking sound to receive an echo gets bundled in a round structure of lipids on the whale's head called 'melon'. For the Belugas the melon is typically prominent and overhangs the rostrum. Almost 40% of the Beluga's body weight of about 1400 kg is fat. The fat is mainly localized right underneath the skin. This blubber avoids a high loss of energy through loss of body heat. Furthermore it provides a streamlined body shape. As the ice pack advances some Beluga populations migrate south to warmer waters in herds of up to 10'000 individuals. Usually the very social Beluga whales live in populations between 2 and 25 individuals though. Within those so called pods they hunt for fish, octopus, squids, crabs and shrimps. The newborn calves weigh about 80 kg and are dark grey. They can swim right after birth and learn survival behaviours by observing and mimicking older pod members. Thereby they frequently communicate with a large repertoire of sounds which has lead to their nickname 'sea canaries'. They reach sexual maturity at the age of eight and thereby their skin turns to its typical creamy white color. Belugas can live up to 28 years when not threatened by the human race.  | |