ArticleslgStudy

biology

Southern resident orcas

Southern resident orcas is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Southern resident orcas rather than just read about it. In short: The southern resident orcas, also known as the southern resident killer whales (SRKW), are the smallest of four communities of the exclusively fish-eating ecotype of orca in the northeast Pacific Ocean. The southern resident orcas form a closed society with no emigration or dispersal of individuals, and no gene flow with other orca populations.

Southern resident orcas — main illustration
Southern resident orcas — illustration

Key takeaways

  • Southern resident orcas belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Southern resident orcas to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Southern resident orcas from memory before moving on to harder problems.

Reference excerpt

The southern resident orcas, also known as the southern resident killer whales (SRKW), are the smallest of four communities of the exclusively fish-eating ecotype of orca in the northeast Pacific Ocean. The southern resident orcas form a closed society with no emigration or dispersal of individuals, and no gene flow with other orca populations. The fish-eating ecotype was historically given the name 'resident,' but other ecotypes named 'transient' and 'offshore' are also resident in the same area. The United States National Marine Fisheries Service listed this distinct population segment of orcas as endangered, effective from 2005, under the Endangered Species Act. In Canada the SRKW are listed as endangered on Species at Risk Act Schedule 1. They are commonly referred to as "fish-eating orcas", "southern residents", or the "SRKW population". Unlike some 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 the July 1, 2024, annual census conducted by the Center for Whale Research, there were only 73 individuals, down from 75 in the 2023 census. This number, however, does not account for the September 2024 birth of L128, bringing the unofficial number to 74 individuals. Lolita, also known as Tokitae, or as Sk'aliCh'elh-tenaut to the Lummi, was captured during the 1970 Penn Cove capture, and died on August 18, 2023, at the Miami Seaquarium. The world's oldest known orca, Granny or J2, had belonged to and led J pod of the SRKW population. Granny was initially estimated to have been born around 1911, which would mean she would have been 105 years old at the time of her disappearance and death which occurred probably in late 2016. However, this estimate was later revealed to have been based on mistaken information and more recent studies put Granny at 65–80 years old.

Society

Social structure All groupings in southern resident society are essentially friendly. The basic social unit is the matriline. A matriline is formed by a matriarch and all her descendants of all generations. A number of matrilines form a southern resident pod, which is ongoing and stable in membership, and has its own dialect which is stable over time. A southern resident calf is born into the pod of its mother and remains in it for life. The southern resident pod is their normal traveling unit. The three southern resident pods form the single clan of this small killer whale community. The clan is possibly a single lineage that split into pods in the past. The clan has a unique stable dialect that shares no calls with other killer whale clans. The following is a listing of southern resident social units:

Community Southern Resident orca community

Clans J Clan

Pods J Pod (25 members) K Pod (15 members) L Pod (34 members)

Matrilines

Note that in several matrilines the matriarch is absent because deceased; nonetheless her descendants continue to associate as a group. Date of census is July 1, 2024. J11s: J27 'Blackberry', J31 'Tsuchi', J39 'Mako', J56 'Tofino' J14s: J37 'Hy'Shqa', J40 'Suttles', J45 'Se-Yi-Chn', J49 'T'ilem I'nges', J59 'Sxwyeqόlh' J16s: J16 'Slick', J26 'Mike', J36 'Alki', J42 'Echo' J17s: J35 'Tahlequah', J44 'Moby', J46 'Star', J47 'Notch', J53 'Kiki', J57 'Phoenix' J19s: J19 'Shachi', J41 'Eclipse', J51 'Nova', J58 'Crescent' J22s: J22 'Oreo', J38 'Cookie' K12s: K12 'Sequim', K22 'Sekiu', K33 'Tika', K37 'Rainshadow', K43 'Saturna' K13s: K20 'Spock', K27 'Deadhead', K38 'Comet', K45 'Prosper' K14s: K14 'Lea', K26 'Lobo', K36 'Yoda', K42 'Kelp' K16s: K16 'Opus', K35 'Sonata' L4s: L55 'Nugget', L82 'Kasatka', L86 'Surprise', L103 'Lapis', L106 'Pooka', L109 'Takoda', L116 'Finn', L118 'Jade', L123 'Lazuli', L125 'Element' L11s: L77 'Matia', L94 'Calypso', L113 'Cousteau', L119 'Joy', L121 'Windsong', L124 'Whistle', L126 'Ken', L127 'Scuba' L22s: L22 'Spirit', L87 'Onyx' (probable brother) L25: L25 'Ocean Sun', the oldest southern resident, has no surviving close relatives since the death of captive Tokitae, aka Lolita, who was probably a member of her matriline. L25 travels with the L22s and L11s. L47s: L83 'Moonlight', L91 'Muncher', L110 'Midnight', L115 'Mystic', L122 'Magic' L54s: L54 'Ino', L108 'Coho', L117 'Keta', plus unrelated L88 'Wavewalker' who is an adult male born in 1993 with no living close relatives and always travels with the L54s. L72s: L72 'Racer', L105 'Fluke' L90s: L90 'Ballena', L128

Splitting in L Pod While J Pod always travels as a unit, and so does K Pod, L Pod orcas are usually encountered in two separate regular units traveling apart. The L4s, L47s, L90, and L72s are one consistent group; the L11s, L22s, L25, and L54s are the other; but sometimes the four L54s strikingly travel independently of all the others. The part of L Pod containing the L11s is often referred to as the L12s after long-lived matriarch L12 Alexis, who died in 2012 after outliving L11 Squirty. L11 had been estimated by association to be L12's daughter, although her birth took place many years before research began.

Social system research

Current knowledge of the society The closed society of the southern resident orcas has exceptionally stable social groupings, and they have been encountered with some predictability in the easily accessible, sheltered coastal waters of the Salish Sea, where scientists have been able to study them more readily than many other cetacean populations. There are no unidentified orcas in these waters, and every individual's place in their society is known. Continuous field studies since Michael Bigg's in 1973 have created a near-complete genealogy of the living Southern Residents, with only one individual born prior to the 1970s remaining alive as of August 2023: L25 Ocean Sun. "The social lives of resident killer whales are without doubt as rich and complex as those of the most advanced land mammals." The lifelong bonds within a matriline are the most significant feature of the Southern Residents' social structure. The basic rule is that individuals remain, for life, in the pod into which they were born and to which they are tied by dialect. By 1990, Michael Bigg and fellow researchers had come to that conclusion, and there has been no fundamental change in the Southern Resident social system documented since then.

… excerpt ends here. Continue reading the full article.

Illustrations

Southern resident orcas: The research vessel Noctiluca of the Northwest Fisheries Science Center in close proximity to an orca
The research vessel Noctiluca of the Northwest Fisheries Science Center in close proximity to an orca
Southern resident orcas: Younger and older Southern Resident orcas hunting salmon prey as a group; sometimes they share the fish
Younger and older Southern Resident orcas hunting salmon prey as a group; sometimes they share the fish
Southern resident orcas: J50 Scarlet at nine months with mother J16 Slick
J50 Scarlet at nine months with mother J16 Slick
Southern resident orcas: Schematic illustration of echolocation pathway in an orca
Schematic illustration of echolocation pathway in an orca
Southern resident orcas: L pod male and salmon prey in Haro Strait, south of Lime Kiln Point State Park
L pod male and salmon prey in Haro Strait, south of Lime Kiln Point State Park

Worked examples

Example 1 — a first encounter with Southern resident orcas

Start with the simplest possible case. Write down what Southern resident orcas claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Southern resident orcas before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Southern resident orcas ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Southern resident orcas

In research
Southern resident orcas appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Southern resident orcas in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Southern resident orcas is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal emotions, Animal intelligence, Cetacean anatomy, so understanding it makes those chapters shorter.
In everyday life
Look for Southern resident orcas outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Southern resident orcas” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Southern resident orcas in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Southern resident orcas means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Southern resident orcas out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Southern resident orcas in simple terms?

The southern resident orcas, also known as the southern resident killer whales (SRKW), are the smallest of four communities of the exclusively fish-eating ecotype of orca in the northeast Pacific Ocean. The southern resident orcas form a closed society with no emigration or dispersal of individuals…

Why does Southern resident orcas matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Southern resident orcas?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Southern resident orcas.

Tags

  • Animal emotions
  • Animal intelligence
  • Cetacean anatomy
  • Cetacean research and conservation
  • Cetaceans of the Pacific Ocean
  • ESA endangered species
  • Endemic fauna of the Pacific Northwest
  • Independent research institutes
  • Puget Sound
  • Southern resident orcas
  • Whale sounds

Keep exploring