Orca / Killer Whale

Description

The orca, also known as the killer whale, is the largest member of the oceanic dolphin family Delphinidae. Adult males can reach lengths of 20 to 26 feet and weigh up to 6 to 8 tons, while females are somewhat smaller at 16 to 23 feet and 3 to 4 tons. Orcas are immediately recognizable by their striking black-and-white coloration pattern, which includes a prominent white eye patch behind each eye, a white chin and throat, a white ventral patch extending from the chin along the belly, and a gray “saddle patch” behind the dorsal fin. The dorsal fin of adult males is the tallest of any cetacean, reaching up to 6 feet in height and standing upright, while females have shorter, more curved dorsal fins of about 3 feet. Each orca’s saddle patch and eye patch shape is unique, allowing individual identification. Their bodies are robust and powerful, built for speed and maneuverability, with large, paddle-shaped pectoral flippers.

Habitat & Range

Orcas have the widest distribution of any cetacean species, inhabiting all of the world’s oceans from the Arctic to the Antarctic and from coastal waters to the open ocean. They are found in particularly high densities in cold, productive waters of higher latitudes. In the eastern North Pacific, several distinct ecotypes occur, including resident, transient (Bigg’s), and offshore populations, each with different ranges, diets, and social behaviors. Transient (Bigg’s) orcas are the ecotype most commonly observed off Southern California and Orange County, where they may be encountered year-round but with increased sightings in spring and summer. These marine mammal-hunting orcas patrol the coastal waters in search of gray whale calves during the spring migration, as well as sea lions, seals, and dolphins. The waters off Dana Point have become particularly well known for orca sightings. Resident orcas, which feed on fish, are more commonly associated with the Pacific Northwest and are rarely seen this far south.

Diet

Orcas are apex predators with remarkably diverse diets that vary dramatically between ecotypes. Transient (Bigg’s) orcas, the type most commonly seen off Orange County, specialize in hunting marine mammals including gray whale calves, minke whales, sea lions, harbor seals, elephant seals, and various dolphin species. They employ sophisticated cooperative hunting strategies, working as a team to separate calves from mothers, exhaust prey through extended pursuit, or create waves to wash seals off ice floes. Resident orcas in the Pacific Northwest specialize in salmon, particularly Chinook salmon, and rarely if ever consume marine mammals. Offshore orcas feed primarily on sharks and other fish. This dietary specialization is culturally transmitted from generation to generation, with young orcas learning hunting techniques from their mothers and other pod members. An adult orca may consume 100 to 300 pounds of food per day depending on the prey type and energy expenditure.

Behavior

Orcas are among the most intelligent and socially complex of all marine mammals. They live in matrilineal social groups led by the oldest female, and in the case of resident populations, individuals may remain with their mother’s group for their entire lives. Each pod has a unique repertoire of calls that function as a group dialect, transmitted culturally across generations. Orcas exhibit a wide range of surface behaviors including breaching, spy-hopping, tail slapping, and pectoral fin slapping. Their hunting techniques are sophisticated and varied, representing some of the most complex cooperative behavior observed in any non-human animal. Orcas have been observed intentionally beaching themselves to catch seals on shore, creating coordinated waves to wash prey from ice floes, and using their tails to stun fish. Females typically give birth to a single calf every three to five years after a gestation period of about 17 months. Females can live 80 to 90 years, while males typically live 50 to 60 years. Post-reproductive females, particularly in resident populations, serve as repositories of ecological knowledge, leading their families to food sources during lean times.

Conservation Status

The IUCN currently lists the orca as Data Deficient, noting that the species may actually comprise multiple distinct species or subspecies that would warrant individual assessments. In the United States, the Southern Resident killer whale population of the Pacific Northwest is listed as Endangered under the Endangered Species Act, with only approximately 75 individuals remaining. This population faces severe threats from declining Chinook salmon runs, vessel noise and disturbance, and bioaccumulation of toxic pollutants such as PCBs and other persistent organic compounds. The transient (Bigg’s) orca population that frequents Southern California waters is not separately listed and appears to be increasing in numbers, benefiting from the recovery of marine mammal populations following the Marine Mammal Protection Act of 1972. Globally, orcas face threats from prey depletion due to overfishing, ocean pollution and bioaccumulation of toxins, habitat degradation, and in some regions, direct persecution by fisheries that view them as competitors. Underwater noise from shipping and military sonar can interfere with their echolocation and communication.