Short-Finned Pilot Whale

Short-Finned Pilot Whale

Mammalia

SCIENTIFIC CLASSIFICATION

COMMON NAME: short-finned pilot whale, shortfin pilot whale, Pacific pilot whale
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Mammalia
ORDER: Cetacea
FAMILY: Delphinidae
GENUS SPECIES: Globicephala (from Latin "globus" - round ball or globe; from Greek "kephale" - head) macrorhynchus (from Greek "macro" - enlarged; "rhynchus" - beak or snout)

FAST FACTS

DESCRIPTION: Extremely similar in appearance to long-finned pilot whale (Globicephala melas). Black in color, some individuals posses a light gray or white patch on the chin. Lighter, gray markings shaped like an anchor present on the chest widening posteriorally. Muscular body with thick tail stock. Forhead bulges over beakless mouth. Skull of G. macrorhynchus is wider, shorter and has fewer teeth than G. melas. The dorsal fin is very large and set forward on the body. The pectoral flippers of G. macrorhynchus are more curved than G. melas and are approximately 1/6 the body length.
MALE Sexual dimorphism is pronounced; males are heavier than females and have much larger melons and dorsal fins
SIZE: Head/body length = 4.7-6.5 m (15.4-21.3)
Dorsal fin height = 30 cm (11.8 in.)
Tail fluke expanse = 130 cm (51.2 in.)
WEIGHT: Mature males are almost twice as heavy as mature females
MALE 1,260-3,150 kg (2,780-6,940 lb.)
FEMALE 600-1,150 kg (1,320-2,540 lb.)
DIET: Primarily squid, also fish; ideally consumes approximately 5% of body weight per day
GESTATION: 15 months average
NURSING DURATION At least 2 years but will begin eating solid food at 6-12 months; calves have been known to nurse for 6-10 years
SEXUAL MATURITY:
MALE 13-16 years at 4.2-5.5 m (13.8-18 ft.); males begin to mate successfully several years after achieving sexual maturity
FEMALE Between 7-12 years; average 9 years at 3.16-3.95 m (10.4-13 ft.); can remain reproductively active up to 37 years
LIFE SPAN: ASDF
MALE Approximately 35-45 years; believed to have a higher mortality rate at all ages than females
FEMALE Past 60 years; large numbers of postreproductive females have been identified in many populations
RANGE: Temperate and tropical oceans worldwide. There is little overlap with the long-finned pilot whale except in temperate waters of North and South Atlantic as well as Pacific waters off of Peru and South Africa.
HABITAT: Pelagic - found both inshore and offshore, seasonally
POPULATION: GLOBAL Estimates using line-transect methods = 219,470
  REGIONAL West coast U.S. = 970
Northern Japan = 5,300
Southern Japan = 53,000
Eastern tropical Pacific = 160,200
STATUS: IUCN Lower Risk/Conservation Dependent
CITES Appendix II
USFWS Not listed

FUN FACTS

1. Name "pilot whale" is believed to originate from the idea that the pods or herds were piloted by a leader whale.
2. Pod structure reflects the highly social nature of pilot whales. Average pod size is 20-90 individuals sharing close marilineal relationships. All age ranges and both sexes are represented although among the adults, females are predominant. Genetic evidence does indicate however that the males breed outside of their family groups.
3. The echolocation ability of pilot whales is equal to that of bottlenose dolphins (Tursiops truncatus). Vocalizations or short-finned pilot whales are in a higher frequency and wider frequency range than those of long-finned pilot whales. They also exhibit group-specific calls.
4. Maximum dive depth may be 500 m (1640 ft.).
5. The observed upper limit through which a pilot whale may remained submerged without surfacing to breath is 15 minutes. Typical submersion periods are generally several minutes below this upper threshold.

ECOLOGY AND CONSERVATION

Generally nomadic. Usually found on continental shelf break, slope waters and where there is high topographic relief and where squid is plentiful. Population studies off of California show that pilot whale groups where greatly affected by the reduced number of spawning squid during the El Niño event of 1982-83. The whales in that area were absent during the period and at least 9 years afterward.

Due to their strong herding behavior, pilot whales are targeted by drive fisheries for their meat, blubber and oil. They are also incidentally taken by drift net, purse-seining, trawling and long line fisheries. This bycatch is not well monitored so the affect on overall population figures is unknown.

Pilot whales are one of the most common species to engage in mass strandings. The cause of these events is not understood but may be the result of disease, illness or geomagnetic disortientation.

BIBLIOGRAPHY

Leatherwood, Stephen, and Reeves, Randall R. The Sierra Club Handbook of Whales and Dolphins. San Francisco: Sierra Club Books, 1983.

Nowak, Ronald M. (ed.). Walkers Mammals of the World. Vol. II. Baltimore: Johns Hopkins University Press, 1999.

Perrin, W. F., Wursig, B., Thewissen, J. G. M. Eds. Encyclopedia of Marine Mammals. Academic Press, 2002.

Martin, A. R. The Ilustrated Encyclopedia of Whales and Dolphins. New York: Portland House, 1990.

http://www.fao.org

http://www.nmfs.noaa.gov/pr/PR2/Stock_Assessment_Program/Cetaceans/Short-
Finned_Pilot_Whale_(N._Gulf_of_Mexico)/ao03shortfinnedpilotwhalengom.pdf