Northern bottlenose whale
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Hyperoodon ampullatus

Names

Azores : Grampa - POR : Botinhoso - ITA : Iperodonte boreale - SPAIN : Hocico de botella - GB : Northern bottlenose whale - GER : Butskopf -NEDER : Butskop - SWEEDS : Nordlig näbbval - NOORS : Bottlenos DEENS : Dogling

Biology

Adults measure 7 to 9 m long, and the males, which are larger than the females, can reach a maximum length of 10 m. Their weight varies between 4 to 5 tons, but they can reach 7.5 tons. They have 1 pair of teeth located in the extremity of the lower jaw, erupted in older males and concealed in females. The cylindrical body of the northern bottlenose whale presents an extremely bulbous forehead (melon), especially in the older males, and a dolphin-like bottlenose beak. This species presents also a V-shaped pair of short grooves on the throat. Young animals are dark brown but, as they age, their coloration changes to a lighter brown, especially on the sides, melon and belly. In the Azores we have observed a few individuals with a completely white head. They can stay submerged for about 1 hour. Females will bear a single calf, 3 to 3.3 m long, every fourth to fifth year. Lactation is estimated to last about 1 year. They can live to 40 years old. They feed mainly on squids, but they can also eat crustaceans and sometimes even echinoderms. Observations indicate that this species has tremendous echolocation capabilities. They produce a vast repertoire of sounds such as clicks, chirps, and whistles with frequencies of 3 to 16 kHz.

Observation

This cetacean was not well liked by the old whalers since it was frequently mistaken at distance for the sperm whale. This mistaken identity was due of to the shape its melon when it emerges, and especially because of its strong blow (about 1.5 m height) oriented forward the same way as the sperm whales. During the summer of 1994, we had the chance to observe them for 3 weeks, and they seem to remain basically in the same geographical region. It was a group of 12 individuals (males, females and young). Their behaviour seemed unpredictable; the amount of time they remained submerged was irregular and changed varied from 10 to 60 minutes. Sometimes they seemed attracted by our vessels and became very active (jumping, lobtailing) but at other times they swam away when we were present. It seemed, however, that they were more at ease as soon as we stopped the engine. They can swim at speeds of 2 to 3 knots without a defined route. It is difficult to mistake this species with any other cetacean, since their large frontal melon identifies and distinguishes them well from all other Ziphidae species.

Cetaceans in the Azores