False Killer Whales
First live specimen documented
Length of pregnancy
Average adult weight
Oldest recorded age for a female
Fastest recorded speed
A false killer whale is the third largest toothed whale in the dolphin family. Although the name seems to imply, the false killer whale, Pseudorca crassidens, is not closely related to the killer whale, Orcinus orca. The name comes from the similarly shaped skulls that both false killer whales and killer whales have. False killer whales do share some superficial similarities, like cone-shaped teeth, with other members of the dolphin family (such as bottlenose dolphins and Pacific white-sided dolphins).
False killer whales tend to have an overall solid, dark grey colouring on their long, slender bodies, although some individuals have lighter grey or even white markings on their undersides and chests between their pectoral (side) flippers. Their elbow-shaped pectoral flippers have an “S” shaped curve that is unique to this species, and they have a small curved dorsal fin positioned centrally on their back. Their elongated head tapers to a rounded snout that hangs over the mouth with no pronounced beak.
There does appear to be some sexual dimorphism in false killer whales – males tend to be slightly larger in size with a more pronounced forehead (melon) than females. Adult males reach lengths of 6 m while adult females measure smaller at 4.8 m. Both sexes weigh 1-2 tons.
False killer whales are found around the world primarily in tropical, subtropical, and subtemperate waters. They are generally thought to be an offshore species, living in deeper waters away from coastal areas, but they have been spotted with some regularity around coastal areas such as the Hawai’ian Islands, Mexico, Costa Rica, and Japan. Although they seem to prefer warmer places, they do wander into cooler waters with– a few individuals seen as far north as Alaska and Norway. Since there are no known populations that spend all of their time in these places they are considered “wanderers.”
Sightings of false killer whales in British Columbia (B.C.) have been reported, but they are considered rare occurrences. In 1987 a group of approx. 12 false killer whales showed up in Puget Sound, Washington. Later that year, one of those animals (presumably) took up residence in Barclay Sound, B.C. and became quite well known to residents of Ucluelet who affectionately named the whale ‘Rufus’. Similarly in 1990 a false killer whale, nick named ‘Willy’, was a frequent sight around Vancouver. The Ocean Wise B.C. Cetecean Sightings Network has collected 177 sightings of false killer whales in B.C. over a 20-year period, although most of these sightings are likely of the same individual (read more about Rufus / Willy the Whale). In July 2014, the Vancouver Aquarium Marine Mammal Rescue team, with help from Fisheries and Oceans Canada (DFO), rescued a month-old false killer whale calf (affectionately named Chester) that had stranded on a beach in Tofino, Vancouver Island. (Read more about Chester)
Due to their pre-dominantly offshore distribution, false killer whales are difficult to study and thus there is currently no estimate of their global population. The best studied group of false killer whales is a cluster of resident animals in Hawai’i that researchers have studied for years.
False killer whales are highly social animals that form strong stable family bonds. They are often found in relatively small subgroups of related individuals, known as ‘pods’, which associate with a larger social group. These pods travel and forage together, likely reinforcing their social bond.
False killer whales have also been known to interact non-aggressively with other whale and dolphin species, such as bottlenose dolphins, Pacific white-sided dolphins, pilot whales, and Risso’s dolphins.
False killer whales have a slender head that tapers to a rounded snout that hangs over the mouth with no pronounced beak.
False killer whales are highly social animals that can be quite acrobatic with spy hops and leaps out of the water.
False killer whales are not closely related to the killer whale.
False killer whales are top predators and are known to eat a wide variety of fish and squid, including large fish like dolphinfish (Mahi mahi), tuna, and sometime sail fish. They forage in subgroups and prey items are shared amoung several individuals in the group.
The false killer whales’ diet overlaps with high-valve species targeted by fisheries, particularly tuna and billfishes. As opportunistic feeders they have learned to pull/steal bait and catch from fishing long lines, a feeding behaviour known as depredation. This behaviour is risky and leads to unsafe interactions with the fishing industry.
False killer whales are long-lived with a maximum age estimated to be over 50 years, likely closer to 60 years.
False killer whales are mammals and give birth to live young. Gestation is 15-16 months, and females only give birth to a single calf every 6-7 years. Calves nurse for about 1.5-2 years. Female false killer whales reach sexual maturity between the ages of 8 and 11, while males mature 8 to 10 years later. At 44-55 years-old females enter menopause where they become less reproductively successful. Similar to killer whales, although unusual for marine mammals in general, these females continue to be a part of the family group, possibly looking after the young of other females in the group.
The false killer whale has no known major predator; however, they are long-lived, slow to reproduce, and naturally rare. False killer whales are primarily impacted by human activity. A major threat is interactions with fisheries. False killer whales are known to depredate (the removal of fish from fishing gear), which can lead to unintentional hooking and/or entanglement, as well as serious injury and/or death.
Other threats include unintentional entanglement or injury in fishing gear (not from depredation), ship strikes, noise pollution, and toxins in the marine environment. False killer whales are long-lived, top predators, and like the orca their bodies accumulate high levels of toxins which can lead to a variety of issues including disease and reproductive issues. They have also been known to eat plastic, and are one of many species known to mass strand.
Permission is granted by the Ocean Wise Conservation Association for classroom teachers to make copies for non-commercial use. This permission does not extend to copying for promotional purposes, creating new collective works, or resale.