Pilot whale
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Globicephala macrorhynchus 

Names

Azores : Peixe boi - POR : Baleia piloto tropicale - ITA : Globicefalo - SPAIN : Ballena piloto - GB : Short-finned pilot whale - GER : Kurzflossen-grinwall - NEDER : Griend - SWEEDS : Grindval - NOORS : Grindhval - DEENS : Grindwal.

Biology

The average adult length is about 4 to 5 m. The female can reach a maximum length of 5 m and the males, 6.5 m. Adults weigh 2.5 to 3 tons. At birth, calves are about 1.4 m and weigh 60 kg. Each jaw has 7 to 9 pairs of conical teeth. Body coloration is very dark grey with a lighter shade extending from the chin to the anus. The head is thick and bulbous (melon shape), a characteristic that reaches its extreme as the animal ages. They feed on cephalopods and small fish (to a maximum of 45 kg per day). Gestation lasts 15 to 16 months and lactation can last as long as 24 months. The average interbirth interval is 3 to 10 years, this interval increasing as the female ages. This species emits a series of different sounds : clangs, whistles, hammer - like sounds; meows. Surprisingly, one of the sounds they make resembles the " moo " of a cow, and this is probably why the old whalers gave this species the common name of " peixe-boi " (bull fish). Sound is used in two main ways - for echolocation and for communication.

Observation

The short-finned pilot whales are frequently observed near other species (e.g., Tursiops truncatus, Physeter macrocephalus). These large Delphinidae are found more frequently in the Azores from April to October (their " cousins ", the Globicephala melanea, were observed by fishermen at different times during the winter). This species was observed during our trips and was present 35 % of the time. The short-finned pilot whales can be confused with the Grampus griseus and with the Pseudorca crassidens. The pilot whales usually occur in large herds (tens of individuals) but we have observed already (July 1993) large groups with several hundred animals. Usually when a group of pilot whales is found, it is possible to observe some animals at the surface because they remain submerged only a few minutes. However, larger males can perform long dives (more than 15 minutes at a time) to depths of 600 m. This species' average swimming speed is about 4 knots but they can reach speeds of 20 knots.

Cetaceans in the Azores