The false killer whale reaches a maximum length of 6 m (20 ft), though size can vary around the world.

The false killer whale has a tendency to mass-strand given its highly social nature; the largest stranding consisted of over 800 beached at Mar del Plata, Argentina, in 1946.

This specimen was unearthed from the Lincolnshire Fens near Stamford in England, a subfossil deposited in a marine environment that existed around 126,000 years ago.

[1][5] The skull was reported as present in a number of museum collections, but noted as lost by William Henry Flower in 1884.

[6] Owen compared the skull to those of the long-finned pilot whale (Globicephala melas), beluga whale (Delphinapterus leucas), and Risso's dolphin (Grampus griseus)–in fact, he gave it the nickname "thick toothed grampus" in light of this and assigned the animal to the genus Phocaena (a genus of porpoises) which Risso's dolphin was also assigned to in 1846.

Based on these and a pod that beached itself three months later in November, zoologist Johannes Theodor Reinhardt moved the species in 1862 to the newly erected genus Pseudorca, which established it as being neither a porpoise nor a killer whale.

[10] William Henry Flower suggested in 1884 and later abandoned a distinction between northern and southern false killer whales.

[11] Still, individuals in populations around the world can have different skull structure and vary in average length with Japanese false killers found to be 10–20% larger than South African ones.

[19] As a toothed whale, a false killer can echolocate using its melon organ in the forehead to create sound, which it uses to navigate and find prey.

[26] A false killer may respond to distress calls and protect other species from predators, aid in childbirth by helping to remove the afterbirth, and has been known to interact sexually with bottlenose dolphins (see Wholphin) and pilot whales,[8] including homosexually.

[32][33] Generally, the false killer whale targets a wide array of squid and fish of various sizes during daylight hours.

[41] The false killer whale is known to be much more adaptable in captivity than other dolphins, being easily trained and highly sociable with other species, and as such it has been kept in several public aquariums around the world, such as in Japan, the United States, the Netherlands, Hong Kong, and Australia.

[9] Chester, an orphaned calf that had been stranded near Tofino in 2014 and rescued by Vancouver Aquarium, probably died from a bacterial erysipelas infection in 2017 at the age of approximately three and a half.

Entanglement can cause drowning, loss of circulation to an appendage, or impede the animal's ability to hunt, and swallowing the hook can puncture the digestive tract or can become a blockage.

[50] The false killer whale regularly beaches itself, for reasons largely unknown, on coasts around the world, with the largest stranding consisting of 835 individuals on 9 October 1946 at Mar del Plata in Argentina.

[9][41] Unlike other dolphins, but similar to other globicephalines, the false killer usually mass strands in pods, leading to such high mortality rates.

[31] The 30 July 1986 mass stranding of 114 false killers in Flinders Bay, Western Australia was widely watched as volunteers and the newly created Department of Conservation and Land Management (CALM) saved 96 whales, and founded an informal network for whale strandings.

Hot-spots for mass stranding exist along the coast of the Western Cape in South Africa; the most recent in 30 May 2009 near the village of Kommetjie with 55 individuals.

[55] On 14 January 2017, a pod of ~100 beached themselves in Everglades National Park, Florida, US; the remoteness of the area was detrimental to rescue efforts, causing the deaths of 81 whales.

[57] No accurate global estimates for the false killer whale exist, so the species is listed as Near Threatened by the IUCN Redlist.

[2] In November 2012, the United States' National Oceanic and Atmospheric Administration recognized the Hawaiian population of false killers, comprising ~150 whales, as endangered.