When females experience menopause
Top travel speed
Longest dive time recorded in B.C
Length of pregnancy
While the name implies a whale, the killer whale (also known as orca) is actually the largest member of the dolphin family (Delphinidae). Without a doubt, they are one of the most distinctive marine mammals in the world with striking black-and-white colouring and a large dorsal fin. Killer whales are sexually dimorphic, meaning males and females look different at maturity. Males may reach up to 9.0 m and 5,568 kg, while females are smaller at 7.7 m and 4,000 kg. Male killer whales start to 'sprout' a tall, triangular dorsal fin (up to 1.8 m in height) in their teen years while females retain a smaller, more curved dorsal fin throughout their lives. In addition to having a taller dorsal fin, adult males have much larger pectoral fins than females and the tips of their tail fluke curve downwards. You can also tell males and females apart by the markings on their underside.
Individual killer whales are commonly identified by pigmentation patterns in the grey saddle patch located immediately behind the dorsal fin, and by natural markings (scars, nicks, etc.) on the dorsal fin itself
Although they are currently recognized as a single species, Orcinus orca, killer whales of British Columbia’s coastal waters are not a single, homogenous group. In fact, three different types of killer whales exist in this area: residents (split into northern and southern populations), Bigg’s (formerly called transients), and offshores. Not only do they not interbreed making them genetically distinct, but they behave differently, their calls are different, and they have completely different diets. They also have subtle differences in their appearance. The images below illustrate the slight differences in resident, Bigg’s (transient), and offshore killer whale dorsal fins and saddle patches used to distinguish the three types.
Killer whales are the most widely-distributed mammal on earth after humans. They can be found in all the world’s oceans, but are most frequently sighted in polar and temperate waters. The distribution of resident, Bigg’s (formerly transient), and offshore killer whales overlaps extensively along the coast of British Columbia.
Resident killer whales are separated into two populations, northern residents and southern residents. As indicated by their name, northern resident killer whales are most commonly seen around northern Vancouver Island and along B.C.’s Central and North Coasts. In the winter they range northward into southeast Alaska and as far south as Washington State, and are often seen in the Johnstone Strait area in the summer. Southern resident killer whales spend their winters as far north as Haida Gwaii and as far south as California. During the summer months, southern residents are commonly seen in the Salish Sea within the Strait of Georgia, the Strait of Juan de Fuca, and around the San Juan Islands. Certain areas along B.C.’s coast are necessary for the survival and recovery of the northern and southern residents. Learn more about critical habitat for resident killer whales here.
Bigg’s (transient) killer whales range all along the western coast of North America, from Alaska to southern California. They are found along the B.C. coast year-round, and are often sighted nearshore where harbour seals and harbour porpoise (their prey) are most common. Although Bigg's are unpredictable, peak sightings occur around Vancouver Island in August and September when harbour seal pups are most numerous. Bigg’s generally frequent the same areas in both summer and winter.
As their name indicates, most encounters with offshore killer whales occur well away from the coast. They are usually found on the continental shelf particularly near Haida Gwaii and more than 15 kilometers off the west coast of Vancouver Island, however groups are occasionally sighted within the inshore waters of Johnstone Strait and the Strait of Georgia. Offshore killer whales have been encountered as far south as Los Angeles, California and as north as the southern Bering Sea.
It is difficult to get an overall census for the number of killer whales in the world, but researchers believe that the global population is at least 50,000 individuals.
The northern resident killer whale population currently number around 300 individuals, whereas the southern resident population numbers at approximately 75. There are an estimated 500 Bigg’s (transient) killer whales in the West Coast Bigg’s population; however, there are numerous other populations of Bigg’s killer whales in California and Alaska that are distinct from our local population. The number of offshore killer whales is less certain, although it is estimated at around 300 individuals.
Resident killer whale pods are matriarchal, meaning that sons and daughters stay with their mother throughout their lives, even after they have offspring of their own. The bonds between siblings usually remain strong even after the mother has died. A matriarch and all of her descendants are referred to as a matriline, and a pod is a larger unit made up of matrilines that travel together. Resident pods typically consist of 10 to 25 or more individuals. A clan is a group of pods that share similar calls or dialects. Learn more about resident killer whale culture and families.
The social system of Bigg’s (transient) killer whales is more fluid than that of residents. Many Bigg’s stay with their mothers for life, but, unlike residents, some leave their mother's group and join up with other Bigg’s once they reach maturity – especially females with young calves of their own. Because they are different from residents in this respect, most researchers don’t refer to Bigg’s social groups as “pods”. Sometimes these dispersing individuals rejoin their birth matrilines after years of separation. Bigg's killer whales usually travel in smaller groups of two to five individuals.
The social organization of offshore killer whales is poorly known in comparison to resident and Bigg’s killer whales. Similar to the two types, offshore groups have been found to be matriarchal, but have a high degree of social fluidity. Offshore killer whales often travel in large groups of 50 to more than 100 individuals.
The activities of killer whales can be grouped into four major categories: foraging (looking for food), resting, socializing, and travelling. All of these activities appear to occur during the day and night. Foraging is the most common activity, comprising a majority of their daily activity. When resting, the whales slow down, group tightly together, become mainly silent, and dive and surface synchronously for three to five minutes or longer. Resting periods can last anywhere from less than an hour to over two hours. Socializing involves physical activity between individuals. Spy-hopping, breaching, tail-slapping, and pectoral-slapping are common during socializing. During periods of social activity, northern resident killer whales will spend a considerable amount of time rubbing their bodies on sloped, pebble beaches, particularly in the Robson Bight (Michael Bigg) Ecological Reserve in Johnstone Strait. Researchers do not know if there is a specific purpose for this beach rubbing behaviour or if it’s for pleasure or recreation. Rubbing behaviour appears to be unique to northern residents – southern residents, Bigg’s, and offshores have never been documented to beach rub anywhere.
Residents spend 60% of their time foraging and the rest of their time resting, socializing, and travelling. Bigg’s spend about 80% of their time foraging, and rest and socialize less than residents. Bigg's engage in conspicuous activities like breaching and playing at the surface less frequently than residents to avoid being detected by their prey. The amount of time offshore killer whales spend foraging, resting, socializing, and travelling is unknown.
Around the world, killer whales feed on prey ranging in size from herring to blue whales. They eat 50-150 kg of food per day and are known to take mackerel, salmon, tuna, squid, sea turtles, stingrays, sharks, seals, sea lions, porpoises, dolphins, grey whales, minke whales, and many other species. However, killer whales in the Northeast Pacific Ocean have very specialized diets and do not feed on all prey that are available to them. Furthermore, their food preferences are learned from family members and shared by other members of their population.
Northern and southern resident killer whales only eat fish, and are salmon specialists. Three-quarters of their annual diet is Chinook salmon. Residents forage cooperatively and prey is often shared between individuals, particularly between mature females and juveniles. Offshore killer whales are also fish-eaters, but their diet is dominated by sharks, including the Pacific sleeper shark and Pacific spiny dogfish. Both resident and offshore killer whales use echolocation to detect their prey.
Unlike the other assemblages, Bigg’s killer whales eat marine mammals, including seals, sea lions, porpoises, and even other whales. They’re known to cooperate to chase, corner and kill their prey, and share their food with group members. Unlike resident and offshore killer whales that use echolocation when searching for fish, Bigg’s killer whales have to stay silent and stealthy when foraging to avoid having their prey (marine mammals) detect them. Instead, Bigg’s will actively listen for the surfacing and breathing noises made by their prey. Only on rare occasions will Bigg’s use quiet, irregular echolocation clicks called “cryptic clicks” while foraging.
Killer whales communicate with each other through a variety of whistles, squeals, squawks, and screams that they produce in the nasal passages beneath the blowhole. Many of these sounds are distinct and produced repeatedly by a given group of killer whales as a set of discrete calls. Killer whales learn their calls from their mothers and other family members.
Resident killer whales are very vocal. They exchange calls and whistles to maintain contact with each other while travelling and foraging. Resident killer whales use sounds as a kind of family badge. Each pod of resident killer whales uses a unique “dialect”, or set of stereotyped calls that help differentiate pods and clans.
On the other hand, Bigg’s killer whales vocalize much less. Marine mammals have far better underwater hearing than most fish and are better at escaping when they detect a predator. To be successful at hunting marine mammals, Bigg's have to be quiet while foraging but they do produce calls during the final stages of an attack or while feeding. The calls of Bigg’s killer whales are quite distinct from those used by resident killer whales.
Much like residents, offshore killer whales are very vocal and produce a number of calls and echolocation clicks while travelling and foraging. However, their calls are different from those of either residents or Bigg’s, and it remains to be determined if they have distinct dialects.
Field studies in British Columbia suggest that males live to a maximum of 60 years while females may reach 70-80 years of age. Average life expectancy is estimated at about 30 years for males and 50 years for females.
Killer whales are mammals and give birth to live young. Some females give birth to their first calf at age 12, but more commonly around 14 or 15 years of age. Usually single young are born; but there is one documented case of twins in British Columbia. The length of pregnancy (gestation period) is 15-18 months and the maximum calving rate is one calf every three years. Calves nurse from their mothers for at least one year, and sometimes up to two or three years. Over their whole reproductive lifespan, females can give birth to approximately five calves and stop reproducing around 40 years of age. Learn more about killer whale mothers.
Forty years ago, killer whales were widely feared and largely misunderstood. Fisherman and mariners often shot at them on sight due to the misconception that these animals posed a threat to their livelihoods and were a danger to humans. Killer whales are no longer thought of as ferocious beasts but rather as intelligent, sensitive, and inquisitive creatures. Today, however, we are threatening killer whales in new ways. Prey availability, underwater noise, physical disturbance, and pollution all pose a threat to whales and their fragile environment. Southern resident killer whales are listed as Endangered under Canada’s Species at Risk Act (SARA), while northern residents, Bigg’s, and offshore killer whales are listed as Threatened.
Learn more about the key threats to killer whales and how Ocean Wise researchers are helping conservation efforts.
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