Short-finned pilot whales are large, with bulbous heads, dramatically upsloping mouthlines, and extremely short or non-existent beaks. The shape of the head varies significantly with age and sex, becoming more globose in adult males. The dorsal fin, which is situated about 1/3 of the way back from the head, is low and falcate, with a very wide base (varying with age and sex). The flippers are long and sickle-shaped, up to 1/6 of the body length. There are 7-9 short, sharply pointed teeth in each tooth row.
Short-finned pilot whales are about 1.4 m long at birth. Adults reach 5.5 m (females) and 6.1 m (males). Males may weigh nearly 3,600 kg. Adult males are significantly larger than females, with large, sometimes squarish foreheads that may overhang the snout, very hooked dorsal fins with thickened leading edges, and deepened tail stocks with post-anal keels.
Except for a light gray, anchor-shaped patch on the chest, a gray post-dorsal fin saddle, and a pair of roughly parallel bands high on the back that sometimes end as a light streak or teardrop above each eye, pilot whales are black to dark brownish-gray. This is the reason for one of their other common names, blackfish (the term blackfish is variously used, usually by fishermen, to refer to killer, false killer, pygmy killer, pilot, and melon-headed whales).
Can be Confused With
In and near the areas of overlap, the short-finned pilot whale is difficult to distinguish from its cogener, G. melas. Fin length can help determine species, but visibility may prevent identification based on this characteristic. Most sightings can be tentatively assigned to species based on the area. Other smaller blackfish, such as false killer whales, and less commonly, pygmy killer and melon-headed whales, may be confused with pilot whales at a distance. Dorsal fin shape is the best clue to distinguishing pilot whales from these species.
The short-finned pilot whale is found in most of the tropical and warmer temperate areas of the world’s oceans, with the exception of the Mediterranean Sea. They rarely venture north of 50°N or 40°S.
North Atlantic – In the western North Atlantic, the short-finned pilot whale ranges from Cape Hatteras (although sightings further north do occur in warmer months) into the Caribbean and the Gulf of Mexico. In the eastern North Atlantic, short-finned pilot whales range from the coast of France in the north to Madeira and the coast of Northwestern Africa.
North Pacific – In the western North Pacific, short-finned pilot whales are found as far north as Japan, although in this area the northern and southern populations differ markedly in coloration, size, body shape, and cranial features; resulting in debate regarding their taxonomic status. In the eastern North Pacific, the short-finned pilot whale is commonly found from the coast of central California (including an apparently resident population near Catalina Island) to Hawaiian waters and the eastern tropical Pacific. On rare occasions, the short-finned pilot whale may be seen in waters as far north as Vancouver Island and Alaska.
Southern Oceans – Distribution of the short-finned pilot whale in the Southern Hemisphere is poorly known, but they have been found in Sao Paulo, Cape Province, Western Australia, Tasmania, New Zealand, and the Indian Ocean.
Ecology and Behavior
Short-finned pilot whale habitat include coastal, pelagic waters. In the eastern Pacific, pilot whales are commonly associated with other species (such as bottlenose, Pacific white-sided, common, and Risso’s dolphins, and sperm whales). Pods of up to several hundred short-finned pilot whales are seen, appearing to live in relatively stable female-based groups. Short-finned pilot whales are among the species of cetaceans that most frequently mass-strand, perhaps due to their strong social bonds.
Females become post-reproductive at around 40 years, but may continue to suckle young for up to 15 additional years, suggesting a complex social structure in which older females may give their own or related calves a "reproductive edge" through prolonged suckling. Calving peaks occur in spring and fall in the Southern Hemisphere, and in fall and winter in the Northern Hemisphere.
Feeding and Prey
Groups of short-finned pilot whales travel abreast in long lines when feeding. The squid genus Loligo is a particularly important prey item for this species. They feed by sucking up their prey. The large tongue of the short-finned pilot whale is depressed and retracted during feeding, causing negative intraoral pressure during capture. They show the tooth reduction typical of other squid-eating cetaceans.
Short-finned pilot whales have a broad diet dominated by: Squid > fish. Squid are the preferred prey of short-finned pilot whales, but they also take fish.
The short-finned pilot whale is listed as ‘Lower Risk, Conservation Dependent’ by the IUCN, and in the United States, the California-Oregon-Washington stock is considered a strategic stock in that incidental take in fisheries has exceeded Potential Biological Removal in recent years. Short-finned pilot whales have been killed directly in drive fisheries in Japan and in harpoon fisheries in the Caribbean and Indonesia. This species has been taken as by-catch in several fisheries in the North Pacific, including driftnet fisheries for swordfish and sharks and the squid purse seine fishery that operates off the California coast.
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