False Killer Whale, Pseudorca crassidens

False Killer Whale, Pseudorca crassidens. Underwater photographs taken in coastal waters off Kona, Hawaii, September 2015. Photography and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The False Killer Whale, Pseudorca crassidens (Owen 1846), is a member of the Delphinidae Family of Oceanic Dolphins. The Genus Pseudorca is one of eighteen genera in the Delphinidae Family and the only species in the Pseudorca Genus. Despite the name,  the False Killer Whale is not closely related to the Killer Whale, Orcinus orca. In Mexico, this species is known as orca falso.

Morphology:  False Killer Whales have slender-bodies with a relatively small, rounded, head. The forehead (melon) slightly overhangs the lower jaw. They have tall, erect dorsal fins, located mid-back that are triangular or curved (falcate). Often, the dorsal fin is badly damaged due encounters with predators. The flippers are long, wide, and have a distinct bulge on the leading edge that gives the fin a boomerang shape. These whales are black in color with a dark gray cape that starts in front of the dorsal fin, with a medium gray fore body and side. They have a whitish patch between the flippers, which narrows to a fine line that runs to another wider patch in the genital region. They reach a maximum of 6.0 m (19 feet 6 inches) in length and 1,360 kg (2,992 lbs) in weight.

Habitat and Distribution:  False Killer Whales are found in schools of ten to more than one hundred individuals and are often mixed in with dolphins and other whales in the open oceans. They are found near the surface to depths up to 500 m (1,640 feet). False Killer Whales are found in all tropical and temperate seas globally. In Mexico they are found in all coastal areas of both the Atlantic and the Pacific; they are also found throughout the Sea of Cortez.

Diet:  False Killer Whales are predatory carnivores, eating primarily fish and squid. They have also been observed eating other whale species. They usually hunt in packs at relatively shallow depths, targeting numerous kinds of fish up to 45 kg (100 lbs), which they share within the pack. False Killer Whales utilize tail slapping to knock large fish several feet out of the water to stun them before consumption; an impressive sight. False Killer Whales usually hunt during the day, making them an easier species to observe than most.

Predators:  False Killer Whales are preyed upon by large sharks and Killer Whales.

Reproduction:  As mammals, False Killer Whales are either male or female for life.  Reproduction is sexual. Females give birth to a single calf, after a fourteen to sixteen month gestation period. Females nurse their calf for eighteen to twenty-four months. False Killer Whales have a low rate of reproduction, offset by long life spans. Males have been documented to live up to fifty-eight years; females to sixty-three years. This allows them to maintain steady populations, however it does increase their risk from overexploitation.

Ecosystem Interactions:  False Killer Whales play an important part in the pelagic food web.  Their collectively hunting with dolphins seems to be somewhat cooperative, if only to cover more ground to find prey. They are known to  host ectoparasites.

Human Interactions: False Killer Whales are hunted in some locations. They also compete with humans for fish stocks and have been known to take caught fish from the lines of anglers resulting in intentionally kills by fishermen. False Killer Whales have not been implicated in attacks on humans, but should always be respected as wild animals. From a conservation perspective False Killer Whales are currently considered to be NEAR THREATENED. Their populations have been in decline which is attributed to hunting, being caught as a by-catch of other fisheries, and bioaccumulation of pollutants.

Synonyms:  Globicephalus grayi, Orca crassidens, Orca destructor, Orca meridionalis, Phocaena crassidens, Pseudorca crassidens meridionalis, Pseudorca grayi, Pseudorca mediterranea, and Pseudorca meridionalis.