Short-finned Pilot Whale (Globicephala macrorhynchus)
Suborder: Odonticeti Family: Delphinidae
Common in Hawaiian waters. Actually a dolphin.
Other known names:
Pothead whale, Pacific pilot whale, Shortfin pilot whale
General description and habits:
Short-finned pilot whales can be confused with their relatives the long-finned pilot whales, but there are various differences. Their flippers are shorter than those of the long-finned pilot whale, with a gentler curve on the edge. They have fewer teeth than long-finned pilot whales, with 14 to 18 on each jaw. Short-finned pilot whales are black or dark gray with a gray or white cape. They have gray or almost white patches on their bellies and throats and a gray or white stripe that 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 stockier as they get older. Adults are 3.5 - 6.5 meters in length. When they are born short-finned pilot whales are about 1.4-1.9 meters long. At birth, short-finned pilot whales weigh about 60kg (135lb). A full grown adult will weigh between 1 and 4 tonnes. Short-finned pilot whales are very sociable and are rarely seen alone. They are found in groups of 10-30, though some pods are as large as 60. They are sometimes seen logging and will allow boats to get quite close. They rarely breach, but may be seen slapping their flukes on the water surface and spyhopping. Before diving, they arch their tails and raise them above the surface. When coming to the surface to breath, adults tend to show only the top of their head, whereas calves will throw their entire head out of the water. Adults occasionally lift most of the body out of the water when swimming at higher speeds.
Identity Keys to use in the field:
Stocky body, Bulbous forehead, No prominent beak, Long flippers with a sharply pointed tip, Black or dark gray color, Fin set forward on body, Tail flukes raised before deep dive, May float motionless at the surface, Frequently seen in very large groups, Prefers deep water, May be approached.
Fish, Squid, and Octopus
Short-finned pilot whales favor tropical areas. The population off Tenerife in the Canary Islands has been studied and they prefer water depths of about 1000 meters (3300 ft). The population in Hawaii is present all year round, but most groups move around, following prey or warm water. They tend to stay offshore, unless squid are spawning, in which case they may move inshore to feed on them. In Japan there are two populations, one northern and one southern.
Hunting/Whaling, Entanglement in fishing nets
When male and female short-finned pilot whales are courting they are thought to bang their heads together under water. Female short-finned pilot whales become sexually mature when they are 9 years old and then have a calf every 4-6 years. They give birth for the last time when they are about 37 years old, but may continue to produce milk and to feed calves in their social group until they are in their 40s. Females are known to survive up to 65 years. They have been known to dive to depths of more than 600 meters.