The famous killer whale or orca whale is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. Distinguishable by its black-and-white patterned body, Orca whales can be found in all of the world’s oceans in a variety of marine environments from Arctic and Antarctic regions to tropical seas.
- Length; 8 metres,
- Weight; 6 tons,
- Life span; Females 80-90 years / Males 50-60 years
- Gestation period: 15-18 months
- Diet: Resident Orca – exclusively fish (primarily Chinook) / Transient Orca – Marine Mammals
Orca will eat between 100-300 pounds of food per day.
Mortality of the young is extremely high during the first six to seven months of life, when 37–50% of all calves die.
Killer whales 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. They have been known to attack baleen whale calves, and even adult whales. Killer whales 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 behaviours, which are often specific to a particular group and passed across generations.
Wild killer whales are not considered a threat to humans, and no fatal attack on humans has ever been documented. Killer whales feature strongly in the mythologies of indigenous cultures, and their reputation in different cultures ranges from being the souls of humans to merciless killers.
Killer whales have good eyesight above and below the water, excellent hearing, and a good sense of touch. They have exceptionally sophisticated echolocation abilities, detecting the location and characteristics of prey and other objects in the water by emitting clicks and listening for echoes, similar to other members of the dolphin family. Like most marine mammals, orcas have a layer of insulating blubber ranging from 7.6 to 10 cm thick beneath the skin. The pulse is about 60 heartbeats per minute when the orca is at the surface, dropping to 30 beats/min while submerged.
The three types of killer whales may be distinct enough to be considered different races, subspecies, or possibly even species. Research off the west coast of Canada and the United States in the 1970s and 1980s identified the following three types:
Resident killer whales
These are the most sighted of the three populations in the coastal waters of the northeast Pacific and around Campbell River. Residents’ diets consist primarily of fish and sometimes squid, and they live in complex and cohesive family groups called pods. Female residents characteristically have rounded dorsal fin tips that terminate in a sharp corner. They visit the same areas consistently. British Columbia and Washington resident populations are amongst the most intensively studied marine mammals anywhere in the world. The grey or white area around the dorsal fin, known as the “saddle patch”, often contains some black colouring in residents.
Fun Fact, residents get often “harassed” by dolphins that will try to place their bodies over the blowholes of the resident orcas, so they do not have choice to breathe by doing a spy hop. Dolphins see orcas as predators of the same fish they want to eat which is why they will “harass” them.
The southern resident killer whales (SRKW) represent the smallest of four resident communities within the northeastern portion of the North Pacific Ocean. The National Marine Fisheries Service listed this distinct population segment of killer whales as endangered, effective in 2005, under the Endangered Species Act. In Canada the SRKW are listed as endangered on Species at Risk Act Schedule 1. Unlike other resident communities, the SRKW is only one clan (J) that consists of 3 pods (J, K, L) with several matrilines within each pod.
As of July 2021, there are only 74 individuals. The world’s oldest known killer whale, Granny or J2, had belonged to and led the J pod of the SRKW population. J2 was estimated to have been born around 1911, which means she would have been 105 years old at the time of her death, and the oldest known orca to date.
The Northern Resident Orca currently comprise around 310 living members.
A5 Pod is a name given to a group of orcas (Orcinus orca) found off the coast of British Columbia, Canada. It is part of the northern resident population of orcas – a name given to the fish-eating orcas found in coastal waters ranging from mid-Vancouver Island up through the Queen Charlotte Islands of British Columbia and into the southeastern portions of Alaska. The orcas of the Northern Resident community are divided into vocally distinctive clans known as the A clan, the G clan, and the R clan. Members of the A5 Pod belong to the A clan.
Over time, studies showed that these congregations of orcas did not make up a complete, distinctive pod. Rather, they were matrilines – a mother and her offspring up to the fourth generation. However, matrilines within a pod frequently socialize with one another, more so than with orcas from another pod – thus still making up a distinct community, and so perpetuating the use of the pod naming.
Clan – ‘A’ ‘G’ ‘R’
Pods – Northern Residents are split up into 15 pods
Similar dialects amongst pods create the social grouping called “clans”. It is believed that the more similar their dialect is within the pods, the more closely related they are. The southern dialect is very different from that of other communities. For instance, northern residents use whistles as their main type of close-range communication and the southern residents use whistles for regular social interactions and long-range communications. Southern residents appear to be much more vocal, but it could be due to their vocal usage during travel and the fact that they seem to travel more than the northern residents.
Transient or Bigg’s
The diets of these whales consist almost exclusively of marine mammals. Transients generally travel in small groups, usually of two to six animals, and have less persistent family bonds than residents. Transients vocalize in less variable and less complex dialects. Female transients are characterized by more triangular and pointed dorsal fins than those of residents. Saddle patches of transients are solid and uniformly grey. Transient’s roam widely along the coast; some individuals have been sighted in both southern Alaska and California.
Dr. Michael Bigg: 1939-1990. Father of killer whale research, department of fisheries, public concern re. unregulated “fishery” and escalating harassment. First census of its kind. Boating public report killer whales. Led to estimate of 250-350 killer whales in BC/WA. Far fewer than believed. He was supposed to be studying seals but began identifying orca as Individuals with unique dorsal fins.
Very little is known about offshore killer whales because they tend to spend most of their time offshore along the continental shelf. Some groups have been sighted in inshore waters and even deep into coastal inlets. Offshore killer whales are typically encountered in groups of 30 – 70 whales or more. Little is known about their social structure.
It is thought that these killer whales eat large ocean fish such as sharks and halibut. Compared to transient and resident killer whales, offshore killer whales have a large proportion of nicks and scarring, possibly from catching sharks. The few offshore killer whales that have stranded had teeth that were significantly worn down, which would also occur from consuming sharks which have very tough skin.
Offshore killer whales are acoustically distinct from resident and transient killer whales, but little is known about how they use their calls and how this differs from resident and Bigg’s killer whale behaviour.
Identifying resident from transient orca
Although they do look slightly different, to the untrained eye the physical differences between resident and transient orca can be difficult to see.
- Transient orca are slightly longer and heavier than resident orca
- Transient orca have a sharply pointed dorsal fin whereas resident orca tend to be more rounded
- The saddle patch (grey mark just behind the dorsal fin) on a transient orca will be solid or ‘closed’ whereas the resident orca will often contain black marks throughout, this is know as an ‘open’ saddle patch
- Transient orca will generally congregate in small groups and hunt close to shore. Resident orca are more social and often travel in larger social family groups
- Since the salmon that resident orca feed on are not particularly sensitive to sound, resident orca will vocalize while hunting
- While hunting prey, transient orca will often dive for long periods and will remain silent relying on the element of surprise