Short-finned pilot whale | |
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Size compared to an average human | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Artiodactyla |
Infraorder: | Cetacea |
Family: | Delphinidae |
Genus: | Globicephala |
Species: | G. macrorhynchus |
Binomial name | |
Globicephala macrorhynchus Gray, 1846 |
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Range map |
The short-finned pilot whale (Globicephala macrorhynchus) is one of the two species of cetaceans in the genus Globicephala. It is part of the oceanic dolphin family (Delphinidae), though its behaviour is closer to that of the larger whales.
Short-finned pilot whales can be confused with their relatives the long-finned pilot whales, but there are various differences. As their names indicate, their flippers are shorter than those of the long-finned pilot whale, with a gentler curve on the edge. They have fewer teeth than the long-finned pilot whale, with 14 to 18 on each jaw. Short-finned pilot whales are black or dark grey with a grey or white cape. They have grey or almost white patches on their bellies and throats and a grey or white stripe which goes diagonally upwards from behind each eye.
Adult males may have a number of scars on their bodies. Their heads are bulbous and this can become more defined in older males. Their dorsal fins vary in shape depending on how old the whale is and whether it is male or female. They have flukes with sharply pointed tips, a distinct notch in the middle and concave edges. They tend to be quite slender when they are young, becoming more stocky as they get older.
The short-finned whale has a stocky body, a bulbous forehead, no prominent beak, long flippers sharply pointed at the tip, black or dark grey color, and the dorsal fin set forward on body. The flukes are raised before a deep dive; they may float motionless at the surface, frequently are seen in very large groups, prefer deep water, and may be approached. Their diets are composed of fish, squid, and octopus.
Adults males are about 5.5 meters (18 ft) in length, whereas adult females only reach about 3.7 meters (12 ft) in length. Adults can weigh from 1,000 to 3,000 kg (2200-6600 lbs) (1,000-3,000 kg). When they are born, short-finned pilot whales are about 1.4–1.9 m (4 ft 7 in–6 ft 3 in) long and weigh about 60 kg (130 lb). Males live nearly 45 years, whereas females can live up to 60 years.
Short-finned pilot whales are very sociable and are rarely seen alone. They are found in groups of 10 to 30, though some pods are as large as 50. In a few sitings of pods, over several hundred animals have also been recorded. Pods are primarily matrilineal, or a female-based society. Some older females have been recorded actually taking care of calves that are not their own. Males are polygynous, meaning they will mate with multiple females at one time or throughout their lives. Pods are often found with around one mature male per every eight mature females. Maturing males will often leave their birth school, but most females will stay in the same pod their entire lives. They are sometimes seen logging and will allow boats to get quite close. They rarely breach, but may be seen lobtailing (slapping their flukes on the water surface) and spy-hopping (poking their heads above the surface). Before diving, they arch their tails and raise them above the surface. When coming to the surface to breathe, adults tend to show only the tops of their heads, whereas calves will throw their entire heads out of the water. Adults occasionally porpoise (lift most of the body out of the water) when swimming particularly quickly.