BC Whales
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Northern Residents

Northern Residents

Northern Residents  |  Biggs (Transient)

Life History

The term ‘resident’ was initially inspired by their reasonably predictable and consistent travel patterns as observed by researchers in the 1970’s. Their range extends from the southern portion of coastal Alaska to the northern half of Vancouver Island, and as exclusive fish eaters, resident populations tend to follow the yearly migration of salmon. Northern residents typically amass in the Johnstone Strait region in the middle of June – just as chinook salmon begin their journey towards the intricate network of rivers and streams along the coast. The whales continue to follow the Pacific salmon migrations, stretching upwards as far as Alaska until the last salmon disappear in late fall.

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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.

 

Social Structure

The Northern resident community of orcas is well known for their strong family bonds and acoustic dialects that separate one pod from another. This highly social community consists of over 200 whales and continues to grow with each season. 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 Northern Resident orcas are associated in larger groups called clans. There are 3 distinct clans within this community. A clan is a collection of pods that share a number of common calls, most likely resulting from a continuous lineage that long ago shared a common 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.

Be sure to listen to the following examples of each clan.