The science is not entirely clear at this point, but it is possible that there are from three to five subspecies, or species, of orcas. The three commonly acknowledges types of orcas today are:
- Resident: these orcas are the most commonly spotted of the three groups. They also live in the Pacific northeast and eat fish and squid. They have complex pods, or groups, and the females have a rounded dorsal fin with a sharp corner. These orcas travel to the same areas consistently, such as the coast of British Columbia and Washington.
- Transient: these orcas feed on marine mammals and travel in smaller groups than offshore orcas, usually only between two and six per pod. The connection between family members appears to be less stable than that which exists in others. Transient orcas live along the coast, with sightings in Alaska and California. These whales are also known as Bigg’s killer whale.
- Offshore: the offshore population of orcas lives in the Pacific northeast and was identified in the late 1980s. They are differentiated due to their large scarred dorsal fins and have been encouraged along Vancouver Island. They gather in groups of between 20 and 75 but little else is known about their habits.
Orca Appearance
Orcas are known for their large dorsal fin, on the whale’s back, and their black and white colors. They have a patch of grey behind the dorsal fin, known as a saddle. Their bodies are tapered, allowing them to swim quickly through the water. Orcas, despite their status as “killers” are not a threat to human beings. There has never been a fatal attack on a human being recorded.
Credit: Minette Layne, CC BY 2.0
Orca Habitat and Habits
Orcas are widely distributed, more so than any other mammal. They live in the coastal areas surrounding most countries and are capable of adapting to any climate. They can be found around the equator as well as in the waters of the North and South pole. It’s in part due to this wide distribution that counting orcas has been difficult. No one is quite sure what their population numbers are, especially as various subspecies or species are considered.
The highest density of whales, scientists believe, is located around the Norwegian coast, along with the Aleutian Islands, the Gulf of Alaska, and off the coast of Antarctica. Other common areas where the whales are spotted around off the coast of British Columbia, Washington, Oregon, Iceland, and the Faroe Islands. A 2006 consensus suggested that there was a minimum of 50,000 individual orcas worldwide at that time.
Orcas are very social animals. They travel together in groups, known as pods, and are led by the eldest female (meaning they have a matrilineal society). Their pods are incredibly stable and sophisticated, with complex and successful hunting techniques vocalizations. These features are passed down through generations and have been described by some scholars as “animal culture.” This is a new line of study that focuses on non-human animals and cultural learning.
Killer whales also have great eyesight and hearing, as well as a powerful sense of touch. This adds to their overall hunting ability, which is already quite sophisticated due to their echolocation abilities. This refers to their biological sonar, or ability to emit calls and listen to eh echos of those calls. They return from nearby objects, helping the animal pinpoint potential prey.
Orca Diet
Orcas have a diverse diet as the largest member of the oceanic dolphin family. Some orcas only eat fish while others hunt larger prey, something that led to their name designation “killer whale.” They prey on mammals, like seals, as well as other dolphins. Orcas have also been known to attack larger whales, like baleen whales. They are apex predators, meaning that there are no animals that prey on them. Despite this, they are listed as a threatened species by the IUCN Red List.
To catch their prey, orcas sometimes Bach themselves to catch seals on land. Meaning, they jump out of the water, land on the ice or shore, and latch their prey in the jaws before dragging it back into the water. Orcas have large teeth, growing up to four inches, or ten centimeters in length. They’re also quite strong, capable of exerting a powerful grip on their prey.
Credit: Christopher Michel, CC BY 2.0
Orca Reproduction
A female orca gives birth to one offspring, once every three to ten years. Their gestation period is around seventeen months and once born, the calf nurses for several times an hour for days until the child is weaned. Female orcas mature around ten years old and reach the height of their fertility around twenty. Orcas are one of the only animals which undergo menopause and still live for a period of time after they’re no longer able to have children. Males are mature at the age of fifteen but don’t reproduce for several more years. They live shorter lives than their female counterparts, around 30-60 in comparison to 50-100.
Threat to Orcas
Orcas, like all marine animals, are at threat from industrial fishing, nets, pollution, chemical spills, sound pollution, and changes in ocean temperature. As large animals at a high trophic level, the killer whale is at particular threat from toxins in the ocean. One particular toxin, polychlorinated biphenyls, can accumulate in their blubber, something that is highly dangerous especially when food is scarce and the whale metabolizes it’s blubber for energy.
5 Interesting Orca Facts
- Orcas are hunted for food and in the belief that they threaten fishing resources.
- Orcas are at risk from chemical and oil spills.
- White killer whales have been spotted in the Bering Sea and around St. Lawrence Island. Female orcas live from 50 to 100 years.
- Infanticide has been observed in the wild.
- Orcas are an important part of many indigenous cultures. The Haida, for example, consider the orca the most powerful of all marine animals.
