False killer whale

Name and taxonomy

Richard Owen described the species in 1846 from a skull dug up in the Lincolnshire Fens in 1843. The skull came from a marine deposit about 126,000 years old. Owen placed the animal among the porpoises and called it the thick-toothed grampus. The species name crassidens means thick-toothed.

John Edward Gray moved it to Orcinus, the orca genus, the same year. In 1861 the first bodies washed ashore in Kiel Bay, and a pod beached three months later. In 1862 Johannes Reinhardt created the genus Pseudorca, which means false orca, for the animal. It sits in the family Delphinidae, the oceanic dolphins. No subspecies are recognised, though Japanese animals run 10 to 20 percent larger than South African ones.

Evolution and relatives

The false killer whale belongs to the subfamily Globicephalinae. Its closest relatives are Risso's dolphin, the melon-headed whale, the pygmy killer whale and the pilot whales. The snubfin dolphins may belong to the same group. The orca, despite the name, is a more distant cousin.

The species can breed with the bottlenose dolphin, and the hybrid is fertile. Both parents carry 44 chromosomes. Kekaimalu, a wholphin, was born at Sea Life Park in Hawaii on 15 May 1985. Her mother was a bottlenose and her father a false killer whale. She bore three calves of her own and died in 2024 at 39.

Appearance

Males measure 3.7 to 6.1 metres and females 3.5 to 5 metres. A large male can weigh about 2,200 kilograms, and females reach about 1,200. Males run about 10 to 15 percent larger than females. A newborn is 1.5 to 2.1 metres long and weighs about 80 kilograms.

The body is black or dark grey, a little paler below, with a faint grey blaze on the chest. The head is rounded and tapers to the front without a beak, and the upper jaw sticks out a little past the lower. The dorsal fin is curved like a sickle and stands 18 to 40 centimetres high in the middle of the back. The flippers are short and pointed, with a bulge on the leading edge that no other dolphin has. The jaws hold 14 to 21 conical teeth above and 16 to 24 below.

Habitat and range

The false killer whale lives in tropical and subtropical waters of the Atlantic, Pacific and Indian Oceans. It rarely goes beyond 50 degrees north or south. Records from cooler seas, such as Britain or British Columbia, are probably strays or animals following warm water. It has been found in the Red Sea and the Mediterranean.

It prefers deep water in the open ocean. Around oceanic islands it comes close to shore. Hawaii holds three separate populations: an offshore group, one in the Northwestern Hawaiian Islands and a small resident group around the main islands. GBIF records the species in 99 countries, a count that includes strandings far outside the normal range.

Diet and hunting

The false killer whale eats fish and squid, and it likes them big. Mahi-mahi, wahoo, yellowfin tuna, bonito and salmon all appear in the diet. It hunts by day and dives to follow prey, with one Hawaiian animal recorded at 927.5 metres. A captive animal eats 3.4 to 4.3 percent of its body weight each day.

Pods spread out to search and then converge when one whale finds a fish. A whale may leap clear of the water with a fish in its mouth. It shakes a large fish until the head and guts fall away, peels off the skin with its teeth and eats the rest. Pod members share food, and a mother will hold a fish so that her calf can feed from it.

The whale also takes marine mammals. It has attacked small dolphins around tuna nets, sperm whales and a humpback calf, and in 2025 more than 50 were seen hunting two humpbacks. A group filmed near Sydney in 2016 killed a young shark. It steals fish from longlines, which is the root of its trouble with people.

Behaviour and social life

The species travels in pods of about 10 to 20, and these pods join into herds of hundreds. Groups of more than 500 have been recorded. While feeding a pod breaks into family groups of 4 to 6. Some animals have been seen in the same pod for 15 years, and the Hawaiian clusters hold bonds that last decades.

Pods appear to be led by mothers, as in pilot whales and sperm whales. Mixed pods with bottlenose dolphins, pilot whales and other species are common, probably because they share feeding grounds. The whale has been seen answering distress calls, guarding other species from predators and helping at a birth. It also mates with bottlenose dolphins and pilot whales.

It rides the bow waves and wakes of ships and leaps over the wake, a habit that helps observers tell it from pilot whales. A pod off Chile cruised at 15 kilometres per hour, and pods have been clocked at about 30. One dive off Japan lasted 12 minutes to 230 metres, and the longest dives probably reach 18.5 minutes.

Communication and senses

Like all toothed whales, the false killer whale finds its way and its food by echolocation. The melon in the forehead focuses the clicks, and it is larger in males. Most clicks fall between 20 and 60 kilohertz, with some up to 100 to 130.

The whales also whistle, squeal and pulse. Researchers can hear the whistles of a pod from about 200 metres away. One observer wrote that each whale seemed to make a different sound at the same time. Populations in different oceans use different calls, as other dolphins do.

Reproduction and life cycle

Breeding happens in any month but peaks from December to January and again in March. The mating system is probably polygynous, though some studies suggest both sexes take several mates. A female carries her single calf for 11 to 15.5 months. If she does not conceive at her first ovulation she keeps ovulating until she does.

The calf swims at once and nurses for 18 to 24 months. It stays in its mother's group after weaning. A female then waits an average of 6.9 years before her next calf. Females mature at 8 to 11 years and males at 8 to 10.

Females stop breeding at about 45 to 55 and live on for years after, as orcas and pilot whales do. In the wild, males live to about 57.5 years and females to about 62.5. One captive female reached 62 and one male 57. Such a slow life means a population recovers very slowly from any loss.

Predators and threats

The orca is the only known predator. Large sharks may also take some, though no attack has been documented. The whale carries worms in its sinuses, lungs, stomach and gut, along with whale lice and barnacles. Heavy worm loads were found in the animals that stranded in Florida in 1976 and 1986.

Fishing gear is the main human threat. A whale that takes bait from a longline can swallow the hook or tangle in the line. Many Hawaiian animals carry scars on the mouth and dorsal fin. The main Hawaiian Islands population fell by 75 percent between 1989 and 2009. As a top predator the whale stores more organochlorine pollutants and heavy metals than other dolphins. A few Japanese villages still take the species in drive hunts, 24 animals between 2010 and 2023.

Population and conservation

Nobody has counted the world population. The eastern Pacific probably holds tens of thousands, and about 16,000 live near China and Japan. Because the total is unknown, the IUCN lists the species as Near Threatened.

The resident population around the main Hawaiian Islands numbered about 139 in 2022 and falls about 3.5 percent a year. The United States listed it as endangered in November 2012 and set aside critical habitat in 2018. The Hawaiian offshore population is about 2,000. All populations are protected under the Marine Mammal Protection Act, and the species sits on CITES Appendix II. Regional agreements in Europe, West Africa and the Pacific islands cover it too.

Relationship with humans

The false killer whale is friendly to people at sea. Animals have swum up to divers and boats and offered fish they had caught. One whale repeatedly brought large salmon to boaters, and Hawaiian whales have handed fish to snorkelers. Fishermen see it differently, as a thief that strips longlines. In the eastern tropical Pacific some are killed for meat or to protect tuna catches.

Aquariums in Japan, the United States, the Netherlands, Hong Kong and Australia have kept the species. It trains easily and mixes with other species, but it can be aggressive toward other dolphins in a tank. It has bred in captivity. Chester, an orphan calf rescued near Tofino in 2014, lived at the Vancouver Aquarium until 2017.

Mass strandings have made the whale famous. The largest, 835 animals, came ashore at Mar del Plata in Argentina on 9 October 1946. In 1986 volunteers in Flinders Bay, Western Australia, saved 96 of 114 stranded whales. In 2005 a storm drove 120 ashore in Geographe Bay, and 1,500 volunteers turned out. In January 2017 about 100 stranded in the Florida Everglades and 81 died.

In culture and myth

No folk tale or legend singles out this species. Sailors lumped it with pilot whales under the name blackfish, and for centuries nobody knew it was a distinct animal. Its own story is a scientific one: a whale described as a fossil, presumed extinct, and then found alive on a Danish beach. The name false killer whale is probably the closest thing to a myth, because the resemblance lies only in the skull.

Its modern fame rests on two things. The first is the wholphin Kekaimalu, born in Hawaii in 1985, whose parents were a bottlenose dolphin and a false killer whale. The second is the stranding. Rescues in Western Australia in 1986 and 2005 drew huge crowds of volunteers and built the country's stranding network. In Hawaii, researchers call the resident whales kama'aina, the word for locals, and treat them as part of the islands.