Three distinct ecotypes of killer whales share the coastal waters of BC: residents, transients and offshores. While the three ecotypes are similar in appearance, their social behaviour’s are quite distinct, including differences in their diet, behaviours, family structure and language. Residents and Transient orcas will not socialize with one another even during the rare occasion they come face to face in the same area.
The common names for orca include ‘killer whale’ , ‘blackfish’ and, more recently, ‘wolves of the sea’.
Males typically range from 6 to 8 metres in length and weigh in excess of 6 tonnes. Females are smaller, generally ranging from 5 to 7 metres in length and weighing about 3 to 4 tonnes. The male dorsal fin can reach a height of 6 feet and the female dorsal fin half that, at 3 feet. They can swim at speeds up to and above 30 knots (56km/hr).
Transients and northern resident orca are sighted most frequently in our research area. In the last 20 years we have only sighted offshore orca four times, three of which occurred in 2015.
Resident Orca
Resident orcas are well known for their strong family bonds and acoustic dialects that separate one pod from another. Resident orcas have rich and established social structures that remain stable throughout generations. At its base, resident orca family structure is maintained by the matriline. Similar to family patterns found in African elephants, orcas (in this case, both male and female) generally remain with their mothers and closely related family members for their entire lives. The bond between mother and son are especially strong, tending to separate only by death. However, when daughters of the matriarch establish their own line of descendants, they may spend more time with their own families, or even break off to form sub-pods as their family expands.
Orcas bonded by closely related matrilines are referred to as pods. Most pods are composed of 1-3 matrilines, and tend to travel as a cohesive group. Not only are they joined by blood, but pod members share a common dialect – distinct from other, more distantly related pods. These unique dialects help researchers easily distinguish between various pods of residents. Dialects are most likely fostered by stable, close-knit relationships among pod members, and passed down through the matriline – learned by calves from their mothers and family.
Different pods of resident orcas are associated in larger groups called clans. There are 3 distinct clans within the Northern Resident community, and 1 in the Southern Redident community. A clan is a collection of pods that share a number of common calls, most likely resulting from long ago through a shared ancestral pod. As the ancestral pod grew in size, it probably broke into smaller sub-pods that developed increasingly distinct dialects as generations progressed. The acoustic tradition of each separate pod was passed on for generations, gradually incorporating slight acoustic variations, and resulting in the variety of dialects that we see today. Using this logic, the closer related members of a clan are, the greater amount of calls they will share.
Using echolocation, resident orcas send out a series of sharp clicks to locate their agile prey. Sometimes, residents work as a collective, ushering a group of salmon into a tight ball to maximize efficiency. Other times, a catch is shared between close family members, especially between a mother and her calf. During hunting, feeding, travelling, and social interactions, resident orcas are highly vocal – layering high-pitched calls into rapid exchanges. Their communication is especially vibrant when different pods come together as a larger collective. Their calls sound excited and joyful – becoming a wandering, echoing dialogue involving dozens of distinct voices.
Resident Orca – A Clan
Resident Orca – A&R Clans
Resident Orca – G Clan
Resident Orca – A Clan (BCD Pods)
Transient (Biggs) Orca
Biggs orca are often referred to as the wolves of the seas. They are the whale that lead to the term “killer whale” since they hunt marine mammals, including other whales. Most commonly, they prey on harbour seals, sea lions, harbour porpoise, dall’s porpoise, and pacific white sided dolphins. But they are on occasion also known to hunt large baleen whales like gray whales, minke whales, fin whales, and humpback whales. Seabirds are also attacked, but not usually eaten. Many times juvenile orca are seen “playing” with seabirds, which might be an important means of developing hunting techniques.
The family structure of Biggs orca is much more fluid, with families breaking apart and joining other families for periods of time. Biggs are also organized matrilineally, but because they feed on marine mammals – females tend to only remain with their mothers until they have had a few calves of their own, at which point they will break away from their natal group and travel as their own matriline. However, like residents, the relationship between a mother and her sons lasts a lifetime. Biggs matrilines tend to be between 2 – 7 whales, with smaller group sizes helping to stay stealthy in the water.
All Biggs orca share a common set of vocal signals, with some small varieties existing, but because of the Bigg’s fluid social order, they have not developed the unique calls/dialects, like resident orcas. Additionally, because this population travels mostly in silence to prevent other species from detecting them, the opportunity for a specific dialect to be passed on to family members is minimized. When we detect Biggs orca call types over the hydrophone we know which population we are recording but cannot determine the family group by distinct acoustic call types. They tend to use passive sonar, listening for the sounds of their prey, such as a splash from a swimming seal or a whistle from a dolphin. This is part of their stealth hunting style. If they were vocal while hunting, it could alert their prey to their presence. However, after a successful hunt, Biggs can be quite vocal when socializing. There is much more to be learned about Biggs orcas, but they are more difficult to study than resident orcas. They tend to be harder to find and easy to lose, but as more research is undertaken throughout their known range, our knowledge and understanding of these enigmatic creatures will continue to grow.
The range of Bigg’s orca on the west coast of North America stretches from southern California to the Aleutian Islands of Alaska. Bigg’s orca cover a large area in search of prey, continuously on the move to maintain their stealth tactic of hunting. If they stayed in the same area for a prolonged amount of time, prey would be alerted to their presence, thus reducing successful hunting. With this on-the-move lifestyle, they can easily travel over 100km a day.
Transient Orca
Transient Orca
