Short-finned Pilot Whale, Globicephalus macrorhynchus

Short-finned Pilot Whale, Globicephalus macrorhynchus. Underwater photographs taken in coastal waters off Kona, Hawaii, September 2015. Photography and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Short-finned Pilot Whale, Globicephala macrorhynchus Grey, 1846,  is a member of the Delphinidae family of Oceanic Dolphins. The genus Globicephala is one of eighteen genera in this family, and there are two species in this genus. They are also known as the Pacific Pilot Whale and in Mexico as Caldrón Negro.

Morphology:  Short-finned Pilot Whales have long, robust bodies. The dorsal fin has a long base, is relatively low, and is falcate (posteriorly concave). They have a large melon, giving rise to the genus name, “Globe Head”. They have a very small beak between the mouth and melon. The mouth curves up toward the eye.  They are black to dark brown in color. Many individuals have a light gray saddle behind the dorsal fin. Some also display a light gray line, curving up and back from the eye.  They are sexually dimorphic with the female reaching a maximum of 5.1 m (17 feet) in length, and males reach 7.3 m (24 feet) in length. The females have life spans of up to 55 years.

Habitat and Distribution:  Short-finned Pilot Whales are found in open water. During the day they spend most of their time at or near the surface. During the day, pods of six to twenty-five whales may be found resting while “logging” or bobbing at the surface. At night, they hunt for food, diving hundreds of meters to find prey. They can reach depths exceeding 1,500 m (4,920 feet). Short-finned Pilot Whales are found worldwide, in tropical and temperate seas and in Mexican waters they are found along the entirety of both the east and west coastlines, including the Sea of Cortez. These whales are often associated with Common Bottlenose Dolphins, Tursiops truncatus.

Diet:  The Short-finned Pilot Whale’s primary food source is squid, but they also eat fish and octopus. They locate their prey by echolocation. In Hawaii, Oceanic Whitetip Sharks, Carcharhinus longimanus, often follow pods of Short-finned Pilot Whales. It is thought that the sharks are taking advantage of the whale’s greater ability to locate food, and also to feed on the whale’s scraps.

Predators: The Short-finned Pilot Whale’s only documented predator is the Killer Whale, Orcinus orca, though large sharks may predate small individuals.

Reproduction:  As mammals, Short-finned Pilot Whales are gonochoric (male or female for life), and reproduce sexually, with internal fertilization. Short-finned pilot whales can breed year-round, but the peak breeding period is July through August, though this can change by geographic region. Both males and females have multiple mates. Females mate with males from outside their pod, who travel between different pods. Gestation lasts  for fifteen months. New born calves range in length from 1.40 m (4 feet 7 inches) to 1.85 m (6 feet 1 inch). They range in weight from 37 kg (82 lbs) to 84 kg (185 pounds). Females give birth about every seven years, and they are the sole caretakers of the calves. Calves will nurse for at least two years, and most calves are independent by age three. Young males disperse shortly after weaning, while young females stay with their mother’s pod. Females reach sexual maturity at 9 years and males at 14.6 years.

Ecosystem Interactions:  Short-finned Pilot Whales are known to host Cestodes, Cetacean Morbillivirus (Paramyxoviridae) and Endo-parasitic nematodes. They also host Epibiont Whale Lice from the family Cyamidae.

Human interactions:  Short-finned Pilot Whales have been hunted worldwide in past centuries. They are still hunted in parts of Asia and the Lesser Antilles. Hunting is illegal through most of their range, but poaching still occurs. Short-finned Pilot Whales are the target of whale watching tours in many locations. Care should be exercised when snorkeling near Short-finned Pilot Whales. They have, on several occasions, grabbed a snorkeler by the legs and dragged them beneath the surface and then release them. This behavior usually only results in moderate bruising and extreme terror for the snorkeler.

Synonyms: Globicephala brachycephala, Globicephala chinensis, Globicephala indica, Globicephala macrorhyncha, Globicephala mela, Globicephala melas scammonii, Globicephala scammoni, Globicephala scammonii, Globicephala scamonii, Globicephala sieboldii, Globicephala ventricosa, Globicephalus brachypterus, Globicephalus macrorhynchus, Globicephalus scammoni, Globicephalus scammonii, Globicephalus sibo, Globiceps macrorhynca, Globiocephala macrorhyncha, Globiocephalus guadaloupensis, Globiocephalus intermedius, and Globiocephalus propinquus.