A pilot whale, also called black fish, is any of the two members of the genus Globicephala belonging to the family Delphinidae, or ocean dolphins. There are two extant species, the short-finned and long-finned whale, with a habitat ranging from the poles to the equatorial waters. These whales are highly social and live in pods of up to 100 members.
There are two species belonging to the genus Globicephala: G. melas or the long-finned, and G. macrorhyncus – the short-finned. They are the only two extant species of the genus which are part of The name of the animal comes from the idea that the pods were coordinated or piloted by a leader, a fact that has been disproven in the past few decades.
Physical description of a pilot whale
The differences between the two species are small, and scientists have a hard time distinguishing one from another. It was thought that the long-finned whales had fewer tooth,
but is has been proven that these traits are more closely related to populations and not species. However, short-finned whales inhabit the warmer waters from the subtropics to the equator while the long-finned ones the subarctic and sub-Antarctic waters. The bodies of the whales are more compact than that of other members of the family, with strong sexual dimorphism. Males are larger and heavier, reaching 6.5 meters and 2,300 kilograms, with females usually measuring 1 meter and 1,000 kg less. The head of the pilot whale is distinctively large and bulbous with the shape of a melon. Usually males can live up to 45 years with females reaching 60 years of age or even more.
These whales feed mostly on small and medium-sized squid. However, the long-finned whales in particular may feed on ocean fish such as cod, mackerel, herring, spiny dogfish and even hake. These whales usually take several deep breaths before diving. They can usually last for 10 minutes without returning to the surface. While these animals are capable of diving at depths of over 600 meters, they rarely go outside the 30 to 60 range, perhaps explained by the abundance of fish. Only the Northern populations such as those near the Faroe Islands may dive deeper to reach squid.
These whales hunt in fast sprints, making them distinctive to most other deep diving mammals that conserve their energy when hunting. They hunt by echolocation, meaning that they emit sounds which bounce off prey and back to them where they have special organs that help them estimate the distance and speed of other organisms.
Behavior and reproduction
Pilot whale species are highly social who usually live in groups of 10 to 30 members, and sometimes up to 100 members. They usually form highly stable social groups where they interact with one another. It has been observed that members are more likely to help close kin compared to other members of the group. Both of these species are polygynous, meaning that males may mate with more females without having control over them such as in a harem. Gestation usually takes 12 to 16 months, with the new born calves being protected and tended for by other females of the group. Pilot whale calves will reach sexual maturity in 9 to 12 years.