Short-finned pilot whales are native to the Atlantic, Pacific, and Indian oceans. There are documented populations off the coasts of Japan, Spain, Africa, California, India, and Hawaii. They prefer tropical and sub-tropical waters and do not linger in areas of colder water such as the Arctic Ocean. In the Atlantic Ocean, they are found as far north as the Madeira Island and the Strait of Gibraltar, which corresponds to an upper limit of 50 degrees North latitude, and a lower limit of 40 degrees South latitude. ("U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments -- 2000", 2000; Hernandez-Garcia and Martin, 1994; Kasuya and Marsh, 1984; Nores and Perez, 2009; Taylor, et al., 2011)
Short-finned pilot whales are found in deep open waters near continental shelves, as well as in coastal areas. They follow schools of cephalopds (Cephalopoda) and linger in areas with quality habitat for their prey. They prefer tropical and subtropical waters. Short-finned pilot whales are found in depths up to 609 m. (Baird, et al., 2002; Shane, 1995; Taylor, et al., 2011)
Short-finned pilot whales are toothed, black whales with gray-white markings on the throat and chest that resemble an elongated anchor. They have a gray saddle around their dorsal fin. Their head region is described as having a bulging forehead, and from this are nicknamed melon heads. They have a beak-like snout and slender, pointed flippers. These flippers are smaller than those of long-finned pilot whales (Globicephala melas), which are otherwise similar in appearance. Male short-finned pilot whales are larger than females. On average, their bodies are 4 to 6 m long. (Britannica, 2011)
Short-finned pilot whales can breed year-round, but the peak breeding period is July through August. Additionally, mating is not usually observed during the winter months. Both males and females have multiple mates. Females mate with males from outside their pod, who travel between different pods. Young males disperse shortly after weaning, while young females stay with their mother's pod. (Johnstone and Cant, 2010; Kasuya and Marsh, 1984; McAuliffe and Whitehead, 2005; Pryor and Norris, 1998; Shane, 1995)
Breeding occurs between males and females from unrelated pods. Gestation lasts 15 months, and calves are usually born in the winter during the time squid are spawning. Newborn short-finned pilot whales weigh 140 g on average. Females are the sole caretakers of the calves, and both young and old females make a contribution. The weaning period lasts 24 months, and the young are independent after 3 years. Adult females typically give birth every 7 years, and have 4 to 5 calves in their lifetime. Young females are sexually mature in 7 to 12 years, and in 9 years on average. Males are sexually mature in 7 to 17 years, and in 14.6 years on average. Males rarely stay within the same pod after reaching sexual maturity. Males have been known to move from pod to pod throughout their lifetime. Females breed until reaching the age of 40, at which they experience menopause. Males can breed until the time of their death, which is normally between 40 and 50 years of age. (Johnstone and Cant, 2010; Kasuya and Marsh, 1984; McAuliffe and Whitehead, 2005; Pryor and Norris, 1998)
Females are the sole caretakers of the young. Females give birth to a single calf, suckle the calf, and teach it to hunt cephalopods (Cephalopoda). Other females within the same pod will help the mother by watching her young while she is out hunting on her own. Females in the menopausal stage will readily help out the younger, breeding females. Males migrate from pod to pod and do not contribute to taking care of young. (Johnstone and Cant, 2010; Kasuya and Marsh, 1984; McAuliffe and Whitehead, 2005; Pryor and Norris, 1998)
The average lifespan of females is 63 years, though they are only able to give birth until age 40. Female short-finned pilot whales go through menopause much like human females do. Males have a higher mortality rate then females and their average lifespan is 46 years. (Kasuya and Marsh, 1984; McAuliffe and Whitehead, 2005; Pryor and Norris, 1998)
Short-finned pilot whales are nomadic and social animals that are primarily nocturnal. Females form kinship pods and males migrate from pod to pod. Within the group, older non-breeding females can serve as a sort of "storage bank" of information for the pod. During the day, short-finned pilot whales are found resting and traveling, and socialize little. It is assumed that they are more active and social at night when they feed. Short-finned pilot whales travel through a large range in a constant search for food. (Kasuya and Marsh, 1984; McAuliffe and Whitehead, 2005; Shane, 1995)
Pods of short-finned pilot whales often stay within a few hundred miles and return to squid spawning sites yearly. They will leave an area if food sources have been depleted and will avoid areas that have not had an abundance of food for several years. ("U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments -- 2000", 2000; Kasuya and Marsh, 1984)
Short-finned pilot whales communicate visually, physically, and acoustically with other whales from their pods. Auditory communication consists of whistles and clicks emitted vocally. Physical communication consists of tail slapping and breaching. Mothers communicate physically by nudging their newborns to the surface. They stay in close physical contact as a means of communication until the newborn is older. Their eyes are specially adapted for life at changing ocean depths. Short-finned pilot whales are sensitive to loud sounds made by humans such as navy sonar and seismic exploration. (Hatfield, et al., 2003; Hofmann, et al., 2004; Robert Heimlich-Boran and Hall, 1993; Taylor, et al., 2011)
Short-finned pilot whales prey upon cephalopods (Cephalopoda) as their main food source, though they also eat small fish. They consume about 45 kg of food per day. Around dawn and dusk, they perform deep dives upwards of 600 meters in search of food. It is assumed that these deep foraging dives happen when benthic-dwelling prey rise and sink in the water column in association with changes in sunlight. (Baird, et al., 2002; Britannica, 2011; Hernandez-Garcia and Martin, 1994; Kasuya and Marsh, 1984; Robert Heimlich-Boran and Hall, 1993; Taylor, et al., 2011)
Humans hunt short-finned pilot whales in varying capacities. No other known predators exist. (Taylor, et al., 2011)
Killer whales (Orcinus orca) have been known to harass pods of short-finned pilot whales, but they tend to not engage each other, even if food is present. (Duignan, et al., 1995; Taylor, et al., 2011; Van Bressem, et al., 1999)
Cetacean morbillivirus of the family Paramyxoviridae has been found in the Atlantic populations, with most individuals testing positive. The earliest known morbillivirus infections were recorded in long-finned pilot whales (G. melas) in 1982. (Duignan, et al., 1995; Van Bressem, et al., 1999)
Short-finned pilot whales are hunted by humans as a food source, to melt blubber into oil, and for bone ornaments and tools. The species has been heavily hunted in the western Northern Pacific. Hunting is now illegal in some locations, but still occurs. (Kasuya and Marsh, 1984)
Short-finned pilots whales can become entangled in drift and gill nets used to catch fish and sharks, causing economic losses for commercial fishermen. (Carretta and Chivers, 2004)
Population trend data is insufficient to determine conservation status for short-finned pilot whales.
Short-finned pilot whales are also known as Blackfish, Pacific whales, and Potheads. (Britannica, 2011)
Christine Dombrowski (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Alecia Stewart-Malone (editor), University of Wisconsin-Stevens Point, Catherine Kent (editor), Special Projects.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
eats mollusks, members of Phylum Mollusca
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
generally wanders from place to place, usually within a well-defined range.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
mainly lives in oceans, seas, or other bodies of salt water.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
breeding takes place throughout the year
young are relatively well-developed when born
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