The false killer whale, a large oceanic dolphin, roams the world’s deep tropical and temperate waters. It is a powerful, highly social predator, making it a subject of ongoing scientific interest.
Physical Characteristics and Nomenclature
The false killer whale possesses a sleek, dark gray to black body, often with a lighter patch on its underside between the pectoral fins. Its head is rounded and conical, lacking a distinct beak. Males can reach lengths of up to 6.1 meters (20 feet) and weigh up to 1,842 kilograms (4,061 pounds), while females are slightly smaller, reaching about 5 meters (16 feet) and weighing up to 1,500 kilograms (3,300 pounds). Their long, slender S-shaped flippers feature a distinct hump on the leading edge, and their dorsal fin is sickle-shaped and positioned in the middle of their back.
The name “false killer whale” stems from the resemblance of its skull and dentition to that of the killer whale (Orcinus orca). Despite this similarity, the false killer whale (Pseudorca crassidens) is a member of the oceanic dolphin family (Delphinidae), making it the fourth-largest dolphin species. While both are powerful marine predators, false killer whales are more slender and possess a different body shape than true killer whales.
Habitat, Diet, and Behavior
False killer whales are found globally in tropical and subtropical oceans, preferring deep, offshore waters. They are pelagic but may approach shore near oceanic islands. These dolphins are highly social, forming strong bonds within their groups. They travel in large pods that can number in the hundreds, though these may break down into smaller subgroups, averaging around 18 members.
Their diet primarily consists of large fish, such as tuna, mahi-mahi, and wahoo, as well as squid. They are active predators, hunting both during the day and at night. False killer whales exhibit cooperative hunting behaviors, working together to corral and capture prey, and have been observed sharing food among pod members. They are capable of deep dives, reaching depths of up to 927.5 meters (3,043 feet), and can swim at speeds of around 29 km/h (18 mph). These intelligent animals use clicks and whistles for communication and echolocation to navigate and locate prey.
Conservation Status
The false killer whale is classified as Near Threatened by the IUCN Red List. This classification reflects concerns about their population, as global estimates are not precise. The main Hawaiian Islands insular false killer whale population, for example, is listed as endangered under the U.S. Endangered Species Act due to its small size, estimated at less than 200 individuals, and historical decline.
The species faces several threats, with incidental mortality from fisheries being a primary threat. False killer whales are known to interact with fishing operations, sometimes taking fish and bait from longlines, which can lead to accidental hooking or entanglement. Habitat degradation, noise pollution from human activities, and the depletion of their prey species also threaten the species.