About ORCAS
Southern Resident orca, J40, shows CWR researchers her teeth and tongue during Encounter #28 on May 26, 2022.
About ORCAS: Landing Points
The killer whale or orca (Orcinus orca) is a toothed whale, the largest member of the dolphin family, and an apex predator in the world’s oceans. Three orca ecotypes inhabit Pacific Northwest waters: Resident, Bigg’s (Transient), and Offshore.
NAMING
The common name is killer whale or orca; other names include blackfish, grampus, and killer.
Most English-speaking scientists use killer whale when referring to the species, although orca is increasingly common—amateur followers and the general public use orca solely.
Pacific Northwest First Nations orca names include:
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Ka-kow-wud (Quillayute, Olympic Peninsula)
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Klasqo’kapix (Makah, Olympic Peninsula)
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Qaqawun (Nootka, west-side of Vancouver Island)
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Max’inux (Kwakiutl, north Vancouver Island)
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Ska-ana (Haida, Queen Charlotte Islands)
J42 Breaching in Haro Strait on September 30, 2021
Individual whales received an alpha-numeric designation based on the letter of their pod and the identification sequence.
See Southern Resident Orca (SRKW) POPULATION.
TAXONOMY
Taxonomy (Scientific Classification)
Kingdom:
Phylum:
Class:
Order:
Suborder:
Family:
Genus:
Species:
Animalia
Chordata
Mammalia
Cetacea
Odontoceti
Delphinidae
Orcinus
Orca
Orcas are one of thirty-five (35) species in the oceanic dolphin family, Delphinidae.
Orcas are in the suborder Odontoceti or toothed whales—referred to as Odontocetes.
Odontocetes differ from other cetaceans (whales and dolphins) because they have teeth instead of baleen (like humpbacks and grey whales).
Orcas are the largest species of oceanic dolphin. Oceanic dolphins are the most diverse group of toothed whales (suborder Odontoceti), with 35 species.
Other similar species include Pygmy killer whales, False killer whales, and Pilot whales.
Click chart to enlarge
Orcas are the most cosmopolitan of all marine mammals and inhabit all of the world’s oceans.
ECOTYPES
Research in the Pacific Northwest has identified three orca ecotypes inhabiting the west coast of the United States and Canada.
Resident:
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Southern Resident (SRKW) designated as J, K, and L pods; currently 73 in this population
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Northern Resident (NRKW) comprised of A, G, and R clans; 34 matrilines; NRKW population over 300
Fisheries and Oceans Canada NRKW Photo-ID Catalogue and Status Report (2019)
Fish-eating Southern Residents, K12s, (above) sharing their favored prey: Chinook salmon.
Marine mammal-eating Bigg’s, one of the T46Bs, approaching its next meal,
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Genetically distinct
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Dorsal fin has a rounded tip, but usually with a sharper angle at the rear corner
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Open saddle patches are common, with significant variations in shape
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Historically travel in large family groups
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Very vocal and socially active
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J pod is the most frequently seen of the Southern Residents
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Do not mix socially with Bigg’s (Transient)
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Evidence of inhabitation for 120,000-140,000 years.
Bigg’s (Transient):
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Population comprised of an estimated 350 individuals; some families seen more frequently than others
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Individuals range from Southern Alaska to Oregon and perhaps Northern California
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More fluid family structure than Residents
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Pointy, shark-like dorsal fin; saddle patch large and uniformly grey (no open saddles documented in Bigg’s)
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Travel in small groups
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Eat marine mammals like seals, sea lions, porpoises, and even other whales
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Keep a low profile when hunting
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Do not mix socially with Residents
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Evidence of inhabitation goes back 300,000 years.
Offshore:
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Little is known about this ecotype and its habits; discovered in 1988
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Genetically distinct from Resident and Bigg’s; appear to be smaller, females characterized by continuously rounded dorsal fin tip (usually lack the sharper angle at the rear corner)
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Saddle patch is usually solid (occasionally open)
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Travel far from shore between the Aleutian Islands and Southern California
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mostly seen off the west coast of Vancouver Island and near Haida Gwaii
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Typically congregate in groups of 20–75 animals (occasional large groups up to 200)
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Diet likely consists of sharks and other long-lived fish species.
Where else on Earth are orcas seen?
Killer whales (orca) are the most cosmopolitan of all marine mammals. There are at least ten distinct ecotypes (prey specialists and generalists) of orcas. They tend to congregate in certain areas, mostly in cold water:
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From California to Alaska, the North Pacific is home to some of the largest concentrations of orcas; the inland waters around the San Juan Islands in Washington State and southwestern British Columbia are probably the best locations in the world to view killer whales in the wild.
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Orcas are most abundant in Antarctica, inhabited by an estimated 25,000-27,000 killer whales, making them the third most abundant cetacean in that area.
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Known and distinct groups of killer whales are also found in the North Atlantic around Iceland, Norway, and Scotland.
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The Peninsula Valdez waters of Argentina are home to a population of killer whales well-known for teaching their offspring to partially beach themselves when hunting young Elephant seals.
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Along the shores of the Crozet Islands, south of Madagascar, a distinct population of orcas has been observed feeding on young sea lions learning to swim.
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Known populations of killer whales live around New Zealand; they eat a variety of prey, including rays.
The life cycle of killer whales (orca) is similar to that of humans.
Southern Resident orca, J1/RUFFLES, was fifty-nine years old at the time of his death in 2010.
J2/GRANNY was estimated to be 70-90 years old when she died in 2016.
Lifespan
Males:
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Between twelve and fifteen years old, their dorsal fin begins growing taller and straighter, indicating the onset of sexual maturity
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Male orcas are sexually mature in terms of physiology, probably in their mid-teens typically; fully physically mature around 25
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They don’t sire offspring until around age 20; the youngest age of paternity is 15
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The most recent estimate of the average (mean) male lifespan is nineteen years; J1 was estimated to be fifty-nine years old at the time of his death in 2010.
Females:
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The estimated average (mean) female lifespan of a SRKW is 35 years
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Females attain sexual maturity in their early teens; among the Southern Resident orcas, J41 is the youngest known mother (K14 gave birth at eleven, too, but the calf did not survive).
Reproduction
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Orca mating and calving take place year-round
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Pregnancies last 18 months, one of the longest gestations of any mammal
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Newborn calves suckle for short periods dozens of times a day; their mother’s milk is extremely rich, possibly containing 40-60% fat
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Calves (Baby Orcas) may start experimenting with solid food at a young age but likely do not fully wean until around the age of three
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Southern Resident orcas have unusually low reproductive output, lower than Northern Resident orcas
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Approximately 69% of Southern Resident pregnancies result in spontaneous abortion (based on work done using hormones derived from fecal samples); spontaneous abortions correlate with hormonal evidence of nutritional stress
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Calf mortality is high: a pregnancy has about a one in five chance of resulting in a calf that survives for more than a year; of the orcas assigned an alpha-numeric designation by CWR since 1976, about one in six died before their first birthday
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The average SRKW female orca birthing rate is currently one viable calf per female every nine or ten years
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Low reproductive output points toward reduced prey availability and toxins as the main threats to successful reproduction; there is evidence that these two threats interact: toxins become more of a danger when salmon abundance is low and a whale’s body condition is poor
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Toxins/persistent organic pollutants, like PCBs, are passed from the mother to the calf during gestation and nursing, which could cause pregnancies to fail and young calves to die
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Controlling for age, SRKW females are more likely to reproduce in years following high Chinook salmon abundance; the survival of calves (and all Southern Residents) correlates with Chinook abundance
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Females are reproductive until about age 40, then experience menopause
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Postreproductive females gain indirect fitness benefits by helping family members—remarkably increasing their number of surviving grand offspring.
CWR BLOGS:
Killer whale reproduction
by CWR Research Director Dr. Michael Weiss.
New evidence of menopause in Bigg’s Transient killer whales by Mia Lybkaer Kronborg Nielsen.
LIFESPAN & REPRODUCTION
BABY ORCA(S)
A baby orca surfaces higher out of the water to ensure it gets a “safe breath” of fresh air.
Newborn:
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Born tail first with a collapsed dorsal fin
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Six to eight feet long, weighing approximately 400 lbs
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Fetal folds are present at birth; it takes three to four weeks for a calf to fill out and fetal folds to disappear
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Orange coloration on underside and eyepatch
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Typically nurse until sometime in their third year, per stable isotope measures.
Newborn, L125, swimming alongside its mother, L86, on February 17, 2021 (Encounter #8). Note the orangish coloration of her underside and eyepatch.
K39 shows her shedding skin when Spyhopping.
First Six Months:
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Stay very close to its mother
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Milk-only diet; usually nurse into its third year; but will begin to eat some solid food around age one
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Surface higher out of the water than juvenile or adult orca to get a “safe breath” of fresh air
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Orange coloration on underside and eyepatch
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Skin shedding occurs
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Gains strength, size, and weight.
Six Months to One Year:
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Begins eating solid food (i.e., salmon), although may continue to nurse into its third year
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Begins to show increased independence
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Shows lots of exuberant and playful behavior
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Gradually loses orange coloration
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Will remain “the baby” until its mother gives birth again (interbirth intervals are highly variable; SRKW, six years).
