Orca (Orcinus orca)

Orca in the Ross Sea

Orcas, also known as killer whales, are among the world’s most easily recognised marine mammals. They are the largest member of the dolphin family and are highly intelligent and social animals. Orcas can be found in all of the world's oceans in a variety of marine environments, from Arctic and Antarctic regions to tropical seas. They have a diverse diet, although individual populations often specialize in particular types of prey. Some feed exclusively on fish, while others hunt marine mammals such as seals and other species of dolphin.

Orcas are apex predators, as they have no natural predators. They are highly social; some populations are composed of very stable matrilineal family groups (pods) which are the most stable of any animal species. Their sophisticated hunting techniques and vocal behaviors, which are often specific to a particular group and passed across generations, have been described as manifestations of animal culture.

Orcas are apex predators, as they have no natural predators. They are highly social; some populations are composed of very stable matrilineal family groups (pods) which are the most stable of any animal species. Their sophisticated hunting techniques and vocal behaviors, which are often specific to a particular group and passed across generations, have been described as manifestations of animal culture.

Types

Orca types. Credit to NOAA Southwest Fisheries Science Center.

Orcas or killer whales have a cosmopolitan distribution and several distinct populations or types have been documented or suggested. Three to five types of orcas may be distinct enough to be considered different races, subspecies, or possibly even species. The IUCN reported in 2008, "The taxonomy of this genus is clearly in need of review, and it is likely that O. orca will be split into a number of different species or at least subspecies over the next few years.".

In the eastern North Pacific Ocean, there are three distinct types of orcas recognized—transient, resident, and offshore. Residents live close to shore in large pods of about 10 to 20 individuals and feed primarily on fish³. Offshore orcas are similar to residents but are distinguished by their smaller overall size and rounded, nicked fins.

Social behaviour

Orcas are highly social animals that live in groups or pods where they hunt together and share responsibility for raising young and taking care of the sick or injured. They have evolved a complex culture: a suite of behaviors animals learn from one another. They communicate with distinctive calls and whistles and can live 60 years or more. They stay in tight-knit matrilineal groups led by older females that model specific behaviors to younger animals.

Orcas have demonstrated captivating social habits, such as living in highly distinctive lifelong pods, as well as exceptional memory and communication skills (amongst other qualities), which have enabled them to acquire immense popularity amongst cetacean admirers. Based on observations both in captivity and in the wild, orcas seem to exhibit a wide range of emotions, including frustration, anger, fear, joy and even self–awareness, which makes them enthralling to observe as social mammals.

Communication

Orcas communicate through pulsed calls and whistles, which form a unique dialect for a family. They express their identity through their cultural habits, and their prey choices are central to this, and so it shapes their language. Orca language is learned and inherited, and just like human babies, orcas can hear their mother in the womb, and so they’re learning their family’s language before they’re born.

The Southern Resident killer whales’ language is so sophisticated that it contains three distinct dialects, one for each of the pods—J, K, and L—with vocalizations that are unique to each pod. However, some calls are common across all three pods, facilitating communication across the community, which allows them to socialize, bond, and mate with other pod members.

Diet

Orcas have a diverse diet, although individual populations often specialise in particular types of prey. Some feed exclusively on fish, while others hunt marine mammals such as seals and other species of dolphin. Their diet consists of chinook and coho salmon, herring, halibut, rockfish, and mackerel.

Killer whale pods have eating habits comparable to the individual food cultures of different countries. Variation in diets across pods is very common, even when they live in the same habitat, as each pod learns a different set of hunting behaviors that dictate what prey they catch and eat.

Hunting

Orcas are precise and efficient hunters that use different strategies depending on their prey and region. They feed on over 140 species, including great white sharks, which they rip open for their livers and hearts¹. They can flip the sharks over to induce a state of paralysis and make them easy to eat. They can also come ashore to hunt seals and sea lion pups, hiding their dorsal fins and beaching themselves.

Some Antarctic orcas use the cunning tactic of regularly hunting in packs and making waves to wash seals off floating ice⁶. These hunting techniques are almost ritualistic and are passed down from generation to generation.

Captivity

Wanda the first captive orca

Orcas have been captured from the wild for display in captive facilities since the 1960's. The first orca to be captured in 1961 was found off the coast of California and given the name Wanda. Many orcas are held in captivity for breeding or performance purposes. They soon became popular attractions at public aquariums and aquatic theme parks due to their intelligence, trainability, striking appearance, playfulness, and sheer size.

The practice of keeping orcas in captivity is harmful to the animals due to the separation from their familial pod during capture, and their living conditions and health in captivity.

Taxonomy

Familia: Delphinidae

Genus: Orcinus

Species: O. orca

See also

• List of deceased captive orcas
• List of living captive orcas

External links

• Orca's Extraordinary Hunting Technique BBC Earth - YouTube