Short-Finned Pilot Whale

## Description

The short-finned pilot whale (Globicephala macrorhynchus ) is one of the two species of cetaceans in the genus Globicephala, which it shares with the long-finned pilot whale (G. melas ). It is part of the oceanic dolphin family (Delphinidae).

It has a worldwide distribution, with a global population of about 700,000, and there may be 3 or 4 distinct populations–two in the Pacific, and one in The Atlantic and Indian Oceans. Its range is moving northward due to global warming. In the Pacific, males average 4–6 m (13–20 ft), and females 3–5 m (9.8–16.4 ft). It generally has a stocky build with black to dark gray/brown skin, and can be distinguished from its counterpart by shorter flippers, fewer teeth, and a shorter beak. They are thought to pursue fast-moving squid typically at a depth of 700 m (2,300 ft), but the maximum recorded depth is 1,018 m (3,340 ft).

The short-finned pilot whale has been reported as being highly playful and social. It typically travels in pods of 10–30 members, typically family, but has been observed moving in groups of several hundred. Like killer whales, it has a matrilineal social hierarchy with an elder female at the head, and a sizable post-reproductive lifespan. It is polygynous, and females often outnumber males 8:1 in a pod.

Pods are known to mass strand, possibly due to sheer accident, geomagnetic anomalies affected biosonar, injury from loud military sonar, or disease. It was historically whaled, and is still whaled today by Japan and the Lesser Antilles, but is protected by several international treaties.

## Appearance

Short-finned pilot whale is a large dolphin with massive and globular head. This globular shape of their head is more prominent in males. Meanwhile, the head of older males often droops, hanging over their mouth. Each jaw of the animal holds 7 - 9 short and strong teeth. Females of this species are shorter and lighter in weight. In addition, the dorsal fin of females in noticeably smaller.

## Distribution

These whales are endemic to offshore tropical, subtropical and warm temperate waters of Atlantic, Pacific and Indian oceans. U.S. population of this species consists of 4 distinct stocks. These are: West Coast, Hawaii, Northern Gulf of Mexico, and Western North Atlantic populations. These 4 stocks are likely to travel south through the western North Atlantic in spring and late winter. The short-finned pilot whales also inhabit the Pacific Ocean, from the Gulf of Alaska to Guatemala. They are known to live in the southern Red Sea, the Indian Ocean and in the Sea of Japan (western North Pacific). The Short-finned pilot whales generally occupy the outer edges of the continental shelf, although they can also occur closer to the shore.

## Behavior

Short-finned pilot whales are social animals. Females of this species gather into kinship pods, whereas males usually move between pods. Older non-breeding females are ’storage’ of information for their pod. These nocturnal animals spend their daytime hours resting and travelling. They are likely to be more active and socialize during the night, when they feed. Short-finned pilot whales are nomadic species, constantly travelling long distances to find suitable food. Members of a pod communicate with each other visually, physically and acoustically. Acoustic communication includes vocalizations such as whistles and clicks, whereas physical communication includes tail slapping and breaching.

## Diet

Short-finned pilot whales are carnivores (molluscivores). The diet of these whales mainly consists of squid, octopus as well as various small fish.

## Reproduction

Short-finned pilot whales are polygynandrous (promiscuous), which means that both males and females have multiple mates. Breeding occurs throughout the year with peak period, lasting from July to August. Gestation lasts for 15 months, after which a single calf is usually born. Males do not take part in rearing their offspring, leaving this responsibility to females. Other females of the pod usually help the female raise her calves. Young are weaned within 2 years old, reaching independence after 3 years old. As soon as weaned, males leave their mother, whereas females continue living in the pod of their mother. Females produce offspring every 7 years. During its life, a female yields 4 - 5 calves. Males of this species reach maturity within 7 - 17 years with an average of 14.6 years old. Females are able to breed at 7 - 12 years of age with an average of 9 years old.

## Population

### Population threats

The biggest threat to the overall population of Short-finned pilot whales is by-catch: these animals are often incidentally caught in gillnets, long-lines and trawls of fisheries, which endanger lives of many whales. As opposed to incidental by-catch, these whales are directly targeted by many fisheries in the waters of Japan, the Caribbean and the Philippines. The Short-finned pilot whales are likely to suffer from sounds, produced by navy sonar and seismic exploration equipment as well as other loud, human-made sounds. Climate change currently causes potentially dangerous changes in the marine environment of these animals.

### Population number

According to the IUCN Red List, the global population size of the Shot-finned pilot whale is unknown for today. However, specific populations have been estimated in following regions: the northern form of Japan - 4,000-5,000 whales; the southern form of Japan - about 14,000 whales; the Philippines: eastern Sulu Sea - 7,492 whales; Tañon Strait - 179 whales; the eastern tropical Pacific - 589,000 whales; waters off the North American west coast - 304 whales; Hawaiian waters - 8,846 whales; the Gulf of Mexico - at least 2,388 whales; the western North Atlantic - 31,139 whales. Currently, Short-finned pilot whales are classified as Data Deficient (DD) on the IUCN Red List

## Fun Facts for Kids

Known as "cheetahs of the deep", these whales practice an unusual hunting technique: when preying, they dive quickly and with torpedo-like movement, gaining a high speed of up to 32 kmph (20 mph) and holding it for up to 200 m (650 feet).

The eyes of these whales are well adapted for life at different underwater depths.

These animals were originally thought to be led or piloted by a single leader, due to which they are currently known as 'pilot whales'.

When diving, Short-finned pilot whales are able to remain submerged for up to 15 minutes.

Short-finned pilot whale is the second largest dolphin only to Killer whale. This animal usually dives for several minutes.

Short-finned pilot whales are capable of diving at depths of up to 500 meters (1640 feet).

## References

https://animalia.bio/short-finned-pilot-whale