Killer whales are the largest members of the dolphin family.
Killer whales have a striking black coloring with grayish-white saddle patch and white belly. Much like their dolphin cousins, they have a conical-shaped head with a small beak and 10-13 conical teeth on both the upper and lower jaw. They have paddle-shaped pectoral fins, and a distinct dorsal fin (curved in females and immature males; straight and up to about six feet tall in males). The male orca's dorsal fin reaches its full height at age 15-25 years.
Unique markings and dorsal fin shape allow Center for Whale Research staff to identify individual orcas. The whale's dorsal fin varies in shape and size, often with distinctive nicks and scars. The saddle patch also differs from whale to whale in shape, size, color, and scarring. In the case of the Southern Resident orcas, individual identification allows CWR staff to maintain a precise census of the population; accounting for every whale on an annual basis.
Orcas are in the suborder Odontoceti, or toothed whales; referred to as Odontocetes. Odontocetes differ from other cetaceans (whales and dolphins) in that they have teeth instead of baleen (such as is the case with humpbacks and grey whales). Orcas (killer whales) are one of 35 species in the oceanic dolphin family, Delphinidae. Although they are referred to as whales, orcas are in fact the largest member of the dolphin family and are physiologically similar to dolphins. Other alike species include Pygmy killer whales, False killer whales, and Pilot whales.
Although orcas tend to aggregate in cold water, they live in all the world's oceans, from the Antarctic to the tropics. Unlike other whales that follow predictable seasonal migration patterns, orcas tend to go wherever their food source is, making their movement patterns much less predictable. Salmon or herring migrations seasonally influence the distributions of some orcas. Other orca ecotypes (e.g., Transients) move in response to the location of their marine mammal prey, such as seals and sea lions.
The life cycle of orcas is similar to that of humans. Female orcas become mature around age 15. Among the Southern Resident orcas, the youngest known mother is J37. Mating and calving take place year round. Gestation varies from 15 to 18 months. Females attain sexual maturity in their early teens. The average birthing rate now one viable calf per female every 9 or 10 years. Females are reproductive until about age 40. Calf mortality is high during the first year of life with approximately 37%–50% of all calves dying. Calves will typically nurse until age two but will begin to eat some solid food around age one.
The average lifespan of female orcas in the wild is 50 years, with several individuals living as long as 80–100 years (estimated).
Male orcas become fully sexually mature at age 25. Between ages 12 and 15, their dorsal fin begins to grow taller and straighter, indicating the onset of sexual maturity. Male orcas typically don’t mate until after the age of 20. Males in the wild live 29 years on average, to a maximum of 50–60 years. J1, who died in 2010, was estimated to be 59 years old.
A captive orca's lifespan is typically much shorter, often by 25 years or more.
Designated endangered in Canada in 2001;
United States in 2005.
The Latin name is Orcinus orca. Common names are orca or killer whale, while other names include blackfish, grampus, and killer. Most English-speaking scientists use the name killer whale, although orca is increasingly used, in particular by the general public. The name killer whale originated from the Spanish whaler’s term “whale killer,” based on their observations of orcas hunting other types of whales. In ancient Roman mythology, the genus name, Orcinus, means "of the kingdom of the dead," or belonging to “Orcus," ruler of the dead. The species name in Latin, orca, literally means "the shape of a barrel or cask," likely due to the orca's body shape. This term is thought to be borrowed from the Greek word that was commonly used to refer to whales.
Size & Weight:
Orcas are the largest members of the dolphin family. Males are larger than females, and adult males are distinguishable (sexually dimorphic) by the increased size of their dorsal fin at sexual maturity
(about 25 years).
Male orcas usually grow to an average of 20-26 feet (6-8 m) and weigh 12,000 lb or more (5,400 kg).
Females evolve to an average of 18-22 feet (6-7 m) and weigh between 8,000–11,000 lb (3,500-5,000 kg).
Calves weigh about 400 lb at birth (180 kg) and are between 7-8 feet long (2-3 m).
The largest male orca on record measured 32 feet (9.8 m) and weighed over 20,000 lb (9,000 kg), while the largest female measured 28 feet (8.5 m) and weighed 15,000 lb (6800 kg).
The grayish-white saddle patch varies from individual to individual in shape, size, color, and scarring.
Photo above: J2/Granny (left), who died in 2016, was the oldest known Southern Resident killer whale. Her estimated age was 106 years. J1/Ruffles (right) was determined to be the oldest male in the SRKW community: 59 years old when he died in 2010.
Sounds of Silence:
Is an Orcas world filled with quiet?
While Southern Resident orcas are mostly quiet at the ocean surface (except for their surfacing "blow" and when they generate loud sounds from slapping and splashing the surface water), they are not as quiet as you might think when they're underwater.
When SRKWs disappear underwater, it's difficult for them to see: each other and where they are heading. In this habitat, underwater visibility is typically no more than 50 meters, and at night is minimal. However, all of the Southern Residents still must communicate with one another, and navigate and hunt for food. Making noise is how they solve these problems. Sound travels very efficiently below the ocean surface and doesn't discern day and night.
J, K, and L pod use echolocation clicks to navigate and locate prey, and various pulsed call types and tonal whistles to communicate (calls seem to be more common than whistles). Researchers have identified at least 25 call types; while not all SRKWs use all calls, they seem to be able to understand the entire language. Researchers have given each of the call types a letter and number designation (e.g., S1).
How Orcas Hear
"The whale receives sounds through the lower jaw, where they are picked up by the fat body in the hollow jawbone and carried to the middle and inner ears.
Sounds are produced in the nasal sinuses of the forehead and focused by the fatty acoustic lens of the melon. The received sound is focused by the fat bodies in the lower jaw to the Bulla, which is a resonating structure linked to the malleus, incus and stapes and thence to the inner ear, as in land mammals. Whales took an air adapted ear and modified the pathway to work underwater, while retaining the delicate internal ear anatomy - a cochlea."
SOUNDS MADE BY Southern Resident Killer Whales
The familiar sound heard when an orca is surfacing (air exchange, exhalation/inhalation); heard and seen by shoreline whale watchers and boaters.
Used underwater for navigation and hunting for prey; referred to as Click Trains (listen for snaps, clicks, and pops).
"Clicks are brief pulses of ultrasonic sound. The reflected echoes act as a biological 'sonar,' giving the whale an exquisite perception of the distance and texture of everything within acoustic range (hundreds of feet to hundreds of yards)."
Whistles & Calls
Used for social communication (listen for different sounds, indicating unique call types).
"Whistles and calls are distinctive and can be heard for miles. Each pod has a unique and recognizable vocabulary called a dialect that is stable over time. Dialects are probably an important means of maintaining group identity and cohesiveness, while distinguishing pod affiliations."
Note. Bigg's/Transient killer whales share the same basic dialect. Offshore orca populations appear to have their own particular dialects.
Quoted material and illustrations from KILLER WHALES Magnificent Creatures of the Salish Sea by Ken Balcomb and Rick Chandler, Bainbridge Island Historical Museum and the Centre for Whale Research © 2016. Used with permission.