Sowerby beaked whale
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Mesoplodon bidens

Names

Azores : Bico de Garrafa - POR : Baleia de bico de Sowerby - ITA : Mesoplodonte di Sowerby - SPAIN : Ballenato de hocico de Sowerby - GB : Sowerby’s beaked whale - GER : Zweizahnwal - NEDER : Gewonespitssnuitdolfijn - SWEEDS : Sowerbys näbbval - NOORS : Nebbhval - DEENS : Naebvhal - JAP : Yoporra ogiha kijira

Biology

Adults measure 4 to 5 m long, but the males - larger than the females - can reach a length of 6 m. Their weight is 1 to 1.5 tons and older animals can reach 3 tons. Their teeth are characteristic: they have only 1 pair of teeth that appear in the middle of the lower jaw. The teeth are visible in the adult males, even with their mouths closed, but are not visible in the females. Their body coloration is bluish gray or charcoal gray. Their head is elongated and extends itself to a long and narrow beak. This species has a V-shaped pair of short grooves on the throat. They feed essentially on squid and small fish. Newborns measure 2 to 2.7 m and they weigh 170 to 185 kg. Gestation lasts 12 months and the lactation period probably lasts for 1 year.

Observation

Our observation statistics show that these animals were present 4 % of the time during our field trips. However, we do not believe that these numbers reflect the real frequency of time that these animals are present in Azorean waters. In fact, the land observations (lookouts) show a much higher frequency and the animals seem to be year-round inhabitants here. These shy animals tend to swim away, and it is very difficult for us to observe them from our vessels, making their identification difficult in the ocean. This species shares habitats with other members of its family (Ziphidae ) such as Gervais« beaked whale and the Blainville«s beaked whale, and it can easily be confused with this last species. The typical position of the two teeth in the male adult can help the observer distinguish them easier. Other characteristic features are the way this animal shows its long beak (making a deep angle) when it emerges or submerges. This species can also be confused with the Cuvier«s beaked whale, but the latter is less evasive to vessels and the orange coloration that some of the Cuvier's beaked whales present can help distinguish them better. A few times we were able to observe a group of 5 to 6 individuals, and the vigia-based lookouts also observed them at a distance, jumping with their bodies fully out of the water, in synchronised pairs, similarly to what we observe with the Tursiops. Their diving times are irregular and can take anywhere from 10 to 20 minutes. Contrary to the sperm whales, it is very difficult to determine their path and the place where they surface.

Cetaceans in the Azores