Orca Behavior: Pods, Social Activity, Communication and Reproduction

Home | Category: Toothed Whales (Orcas, Sperm and Beaked Whales)


orca tail slapping

Orcas are diurnal (active mainly during the daytime), motile (move around as opposed to being stationary), sedentary (remain in the same area), territorial (defend an area within the home range), and social (associates with others of its species; forms social groups). Home range size is unknown, but some studies have shown that orcas live with their pods together in their home range for many years. While home range size is unknown, they have been documented to swim up to 160 kilometers a day. [Source: Emily Burnett, Animal Diversity Web (ADW) /=]

Many scientists say that individual orcas have personalities. When around tourist boats and scientists, some calves are shy and stay close to their mothers. Other are more friendly and independent, approaching boats and show off. Orcas sleep five to eight hours a day, either drifting on the surface, where they can breath, or taking in lungs full of oxygen, and diving to the seabed and settling down there.

Orcas are frequently observed breaching (leaping out of the water), slapping their flippers on the water, spy-hopping (lifting their heads and front flippers out of the water and looking around), doing side rolls, and lobtailing (lifting their flukes high and whacking them down hard on the water). Spyhopping is fairly common. Orcas do it survey their surroundings. They often do it when tourist boats approach so they can get a look at the boat and see who is on it. Orcas like to show off and sometimes seem to perform for tourist boats. One biologist told the Washington Post, “I have seen mother’s toss their babies out of the water with their snouts. Young males show us the salmon they just caught.”

Websites and Resources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Fishbase fishbase.se; Encyclopedia of Life eol.org; Smithsonian Oceans Portal ocean.si.edu/ocean-life-ecosystems ; Monterey Bay Aquarium montereybayaquarium.org ; MarineBio marinebio.org/oceans/creatures

Orca Swimming and Beach Rubbing

Orcas spend most of their time at shallow depths, but occasionally dive several hundred meters depending on their prey. By some reckonings they are the fastest marine mammal and have been timed at 55.5 kilometers per hour (34.5 mph). Porpoising is when an an orca soars up and plunges back down into the water in a single motion, exposing an arched back like a porpoise or dolphin. This method of surfacing requires less energy than swimming in the turbulent waves.

In general, toothed whales like orcas are fast swimmer. They have fused neck vertebrae, which increases stability when swimming at high speeds but decreases flexibility, rendering them incapable of turning their heads. When swimming, toothed whales rely on their tail fins to propel them through the water. Flipper movement is continuous. They swim by moving their tail fin and lower body up and down, propelling themselves through vertical movement, while their flippers are mainly used for steering. [Source: Wikipedia]

Describing a habit of a group of Pacific Northwest orcas, Craig Welch wrote in National Geographic: The ghostly black-and-white procession steamed in like a team of U-boats, low and fast...In waters barely 10 feet deep, the creatures slowed and rolled to their sides. Bodies partially submerged, the fans at the end of their tails — their flukes — wagging, the whales began to twist and shimmy. One by one, each scuffed its side and belly on the stones, like grizzlies scratching against the pines. [Source: Craig Welch, National Geographic, April 15, 2021]

John Ford has studied killer whales for more than 40 years. He’s seen this phenomenon, called beach rubbing, countless times. He can’t say for certain why the animals do it. He suspects it’s a form of social bonding. A larger question, though, has gnawed at him for much of his career: How come these orcas, do it, but not their nearly identical neighbors just to the south? Beach rubbing is routine among this population, called northern residents because they ply inland seas during summer and fall between the Canadian mainland and Vancouver Island. Not so their neighbors to the south. The orcas around the border with Washington State live, have never been documented performing this ritual.

Orca Social Behavior

Orcas are highly social, and most live in social groups called pods (groups of related individuals seen together more than half the time). Individual whales tend to stay in their original pods. Pods typically consist of a few to 20 or more animals. Pods with around 50 individuals have been reportedly. Larger groups sometimes form for temporary social interaction, mating, or seasonal concentration of prey. There has even been reports of hundreds of individuals gathering in place, but these are generally a temporary associations between a group of smaller pods. [Source: NOAA]

Orcas social structures are complex. Individuals in pods are generally multiple generations of related individuals and made up of about 20 percent mature males, 20 percent calves, and 60 percent females and immature males. There is limited dispersal from the maternal pod and young whales are always part of their mother's pod. Individuals in pods swim within 100 meters of each other and coordinate their activities. [Source: Emily Burnett, Animal Diversity Web (ADW) /=]

Orcas share prey and rarely leave the pod for more than a few hours. Orcas teach pod members through apprenticeship. Skill in hunting and parenting are among the skills taught to younger whales.

Orca Pods and Communities

Orcas are very family-oriented animals. A typical pod consists of a matriline’several generations led by senior matriarch — or several closely related matrilines. From the best that can be determined members of resident pods stay with their mothers their entire life and remain together the lifetime of their members.

Orca pods are often led by founding matriarchs. Among other things these “wise mothers” teach their calves to avoid fishing boats, thus preserving the pod’s memory. Norwegian orca expert Dr Tiu Similä told National Geographic: “I don’t know how they communicate this. Maybe they just lead the others away when they hear a boat’s motor. But they have some way of telling them, Look out — that’s bad, that’s dangerous.” [Source: Virginia Morell, National Geographic July 2015]

A pod typically has 10 to 40 members. It has its own dialect of calls and regular travel patterns within a seasonal range. Members make calls about half the time they are submerged and frequently use sonar to locate prey. Pods with common ancestors or dialects are considered clans. Resident pods have the most stable society known among mammals. Pods remain unaltered except for births and deaths. They consist of up to four generations: great grandmothers, grandmothers, mothers and sisters and their offspring, including mature males.

Clans that share a range with other clans are known as communities. Different communities speak different dialects and have different traditions and customs and are different genetically. Aggression within communities is largely unknown and different communities generally ignore each other. In western North America: there are four communities of residents, with around a total of about 100 members each: 1)the Aleutian residents that occupy an area from Kodiak Island westward through the Aleutians; 2) the Southern Alaska residents that occupy an area from Kodiak Island to the southern tip of Alaska; 3) the Northern residents, made of about 200 whales in 16 pods, that occupy an area along the British Columbia coast from the southern tip of Alaska to Vancouver; 4) the Southern residents that occupy an area from Vancouver to Monterey Bay, California. Resident communities in the north appear to be doing better than those in the south in part because salmon stocks there remain strong.

20120522-killer whale ickr_-_NOAA_Photo_Library.jpg

Orca Social Activities

Orcas are very social. They tend to stick close together. When they are a few hundred meters apart they often communicate and echolocate frequently presumably to check where everyone is and what they are doing.

Off of Vancouver orcas have been observed going through a bizarre greeting ritual. When two strange pods meet each other the members of each pod form a line for 10 or 30 seconds before mingling. One scientist told Douglas Chadwick he saw a group of orcas exhibit behavior similar to that of humans participating in a festival. He said one season he noticed a number of orcas “traveling along with a recently caught salmon draped over their pectoral fins or on their heads. This phenomena, or fad, or whatever it amounted to, was fairly common for part of the season,” he said but he never saw it again after that.

Certain pods from the northern resident community rub against smooth pebbles near beaches on Vancouver Island. Reasons they did this is not known. Perhaps it is to remove dead skin or itchy parasites or simply because it feels good. Only some pods do this and some scientists believe it passed on from one member to another and thus represents a form of culture. Nearby pods in the southern resident community only engage in the practice. They are more partial to to in showy aerial displays that northern resident pods don’t engage in.

Orcas remain under the control of their mothers for long periods of time and females are the dominant personalities in pod life. In resident pods it was once thought that adult males were harem bulls. But that is not the case. As Chadwick wrote in National Geographic they “are more like momma’s boys that never leave their family.”

Orca Culture

On the difference between the British-Columbia-based northern resident group and Washington-state-based southern group of orcas in the Pacific Northwest, Craig Welch wrote in National Geographic: The southern residents have their own conventions. They hold “greeting ceremonies,” facing off in tight lines before exploding in underwater parties of rubs and calls. That’s exceedingly rare up north. Southern residents are aerialists, performing twisting leaps and belly flops. Northern residents breach far less. Some years the southern residents push dead salmon around with their heads. Not the northerners: They occasionally headbutt one another, bumping noggins like bighorn sheep. “They just swim at each other and sort of collide,” orca researcher John Ford says. Beach rubbing is routine among this population, called northern residents because they ply inland seas during summer and fall between the Canadian mainland and Vancouver Island. Not so their neighbors to the south. The orcas around the border with Washington State, where I live, have never been documented performing this ritual.[Source: Craig Welch, National Geographic, April 15, 2021]

The two populations don’t even converse with the same vocabulary. Northern residents emit elongated, shrill, metallic squeals that sound like air escaping balloons. Southern residents add monkey hoots and goose honks. To Ford’s practiced ear, the pitches and intonations sound as different as Mandarin and Swahili.

Yet in every other meaningful way, the northern and southern residents are indistinguishable. For months at a time, they occupy adjacent seas. Their ranges overlap. Although many varieties of killer whales exist around the world, the northern and southern whales share almost identical genetics...How could two groups from essentially the same place be genetically similar and yet speak and act so differently? For years, Ford and a few colleagues would only whisper what this paradox implied. Is it possible that these complex social beings weren’t driven solely by the inherited twitch of genetic instinct? Were killer whales passing on unique traits influenced by more than their environment or DNA? Could whales have their own cultures?

Orca Grief and Empathy?

In 2018 an orca known as Tahlequah who lived off Washington state pushed the carcass of her newborn, which had died shortly after its birth, around with her snout for 17 days. “For years scientists vigorously avoided using emotional terms like happy, sad, playful or angry when describing animal behavior,” writes Joe Gaydos, who oversees a university program in Washington State to protect marine life through science and education. But Gaydos and many whale biologists believe Tahlequah’s behavior was a show of grief. [Source: Craig Welch, National Geographic, April 15, 2021]

Dr Tiu Similä, an orca expert in Norway, describes an interesting story about an orca. Virginia Morell wrote in National Geographic: In 1996 a team spotted a calf with a spine and dorsal fin that had been severely injured, probably from a boat strike. ““We named him Stumpy because of his damaged dorsal fin,” Similä said, adding that she doesn’t actually know whether the calf is a male or a female. “He’s not like other killer whales. He can’t hunt, and they care for him.” [Source: Virginia Morell, National Geographic July 2015]

“Instead of living with a single pod, Stumpy swims with at least five different ones, all of which feed him. Once, Similä watched as two females came dashing through the waves, each carrying a large herring for Stumpy. She thinks the orcas understand that a boat injured him, because they keep him away from boats. “Stumpy is the biggest mystery to me. I don’t know what will happen when he becomes sexually mature,” Similä said. “But the other orcas know he needs help, and they help him.”

Matriline chart 2009

“Some researchers have suggested that an orca pod has such tight social bonds that its members respond to other animals and their environment as a single-minded group. That may be why entire pods strand when only one sick member heads for shore. And why some males die after the death of their mother. Perhaps it’s also why so many orcas help Stumpy.

Orca Communication and Echolocation

Orcas communicate with vision and sound and sense using vision, touch, sound, echolocation (emitting sound waves and sensing their reflections to determine the location of objects) and chemicals usually detected by smell. Orcas rely on underwater sound to feed, communicate, and navigate. Pod members communicate with each other through clicks, whistles, and pulsed calls. Each pod in the eastern North Pacific possesses a unique set of calls that are learned and culturally transmitted among individuals. These calls maintain group cohesion and serve as family badges. [Source: NOAA]

There are three categories of vocalizations used by orcas: 1) whistles, 2) discrete calls, and 3) clicks. According to Animal Diversity Web: Vocalizations are used both for communication and navigation. They use discrete calls and whistles when communicating within and among pods. Each pod has their a discrete dialect that sounds slightly different from that of other pods. This dialect has been shown to stay the same in a pod for up to six generations. Clicks seem to be used only for echolocation (emitting sound waves and sensing their reflections to determine the location of objects). Orcas do have good vision, but in dark water their vision is not helpful in catching prey or navigating. As in other toothed whales, orcas use sonar to perceive their aquatic environment. [Source: Emily Burnett, Animal Diversity Web (ADW) /=]

The whale's ears are very small openings behind the eyes, which have no outer flap. The orca hears the whistles and clicks through an auditory bulla (earbone complex) in its lower jaw. The sound waves enter through the jaw where they then enter into the earbone complex. In this auditory bulla, there are bones that are like the bones found in the human ear. They waves travel trough these bones, then enter into the brain via an auditory nerve.

Orca group size
An orca’s brain's is very good at detecting and processing sound. According to Business Insider: Sound travels four times faster in water than air, and orcas take advantage of that by sending out pulses, clicks, and whistles to scan the area around them like radar — an ability called echolocation. "Orcas are very good at detecting the direction of sound," said Lori Marino, founder and president of The Whale Sanctuary Project and a neuroscientist who studies cetacean intelligence. They use echolocation not just to communicate with each other and detect obstacles, but also to hunt prey, and even target specific organs within that prey. Case in point, orcas can use echolocation to detect fish up to 500 feet away and use it to identify the size of the fish and go for larger prey, like older Chinook salmon. [Source: Emily Swaim, Business Insider, May 31, 2023]

Echolocation may also help explain how orcas along the coast of South Africa — who seem to love the taste of fatty, high-calorie shark liver — have been observed tearing away the liver on the first bite. They must know where the liver is located, and echolocation might help explain why. Marino said calculating the origin and nature of each sound they hear likely requires "very complex neurobiological computations." Scientists believe orcas are able to do these calculations thanks to the shape of their wrinkly brains.

Orca Language and Dialects

Orcas make an array of plaintive calls to contact one another and relay information over large areas. They navigate with active sonar, which can be switched on when traveling closely with a pod. Communication is especially important in dim waters, where orcas often operate. Resident orcas make a lot of noise whereas transients tend to be very quiet.

When they are playing or socializing killer make noises such as burbles, squeals, whistles, raspberries and snorts. Each pod has its own dialects with unique calls in terms of pitch, pattern and the numbers used. Often the closer pods are to one another the more similar their dialects are. Young whales learn a dialect from their mothers and old siblings. They also learn to recognize the dialects of other pods.

Residents and transients have different dialects, arguably different languages. Seals can tell the difference between the two and have been observed swimming next to fish-eating residents but will staying clear, preferably out of the water, when they hear mammal-eating transients. In one experiment scientist played recordings of transient orcas close to harbor seals, who quickly ran for cover. When noises of resident whales were made the seals ignore them.

Orcas in Norway produce clicks, whistles and zipperlike sounds. There, each orca pod uses its own distinct language of notes and tones. Russell McLendon wrote in Mother Nature Network“Orcas are among the few animals capable of vocal learning, or the ability to pick up new vocalizations by imitating someone else's. It's the basis for language, and it lets pods of orcas develop "dialects" that are likely passed down from generation to generation. Just six groups of animals are known to use vocal learning: parrots, songbirds, hummingbirds, bats, cetaceans and humans. Countless others vocalize, but their sounds are almost always innate, not learned. Many also use auditory learning to make associations with sounds, like a dog learning how to respond to the sound "sit." Only true vocal learners, however, can say "sit" after hearing it. [Source:Russell McLendon, Mother Nature Network, October 9, 2014]

Orcas Learn Dolphin Language

Orcas who spent time around bottlenose dolphins learned to imitate their clicks and whistles, a study published in in 2014 reported: “"We had a perfect opportunity because historically, some orcas have been held with bottlenose dolphins," study co-author and marine biologist Ann Bowles said. "Orcas seem to be really motivated to match the features of their social partners." [Source:Russell McLendon, Mother Nature Network, October 9, 2014]

Russell McLendon, Mother Nature Network: “The researchers based their findings on three captive orcas who've spent extended periods of time with bottlenose dolphins. By studying old recordings of those animals' calls as well as the calls of orcas and bottlenose dolphins who lacked such cross-species exposure, they were able to test how much the orcas adjusted their own vocalizations to mimic their distantly related companions.

“Those three orcas produced 17 times as many "click trains" and up to four times as many whistles, the researchers write, "making their relative usage of vocalization categories more similar to those of dolphin social partners." The acoustic features of their calls were also less distinguishable from those of bottlenose dolphins, and one of the orcas even learned to produce a novel chirp sequence that humans had taught to the bottlenose dolphins before she was introduced to them.

“All three spoke bottlenose with an orca accent, though. They often whistled at lower rates than native speakers, and they mostly altered orca sounds to resemble bottlenose sounds rather than making totally new noises. One orca was better able to imitate the bottlenose calls, but even her attempts "contained abrupt steps in frequency that were not typical of the dolphin's stereotyped whistle." This may be because orcas have difficulty producing some bottlenose sounds, the researchers suggest. "There's been an idea for a long time that orcas learn their dialect, but it isn't enough to say they all have different dialects so therefore they learn," Bowles says. "There needs to be some experimental proof so you can say how well they learn and what context promotes learning."

Orca Food and Hunting Behavior

Orcas are arguably the ocean’s top predator, eating near the top of the food chain. They often use a coordinated hunting strategy and work as a team to catch prey. Although the diet of orcas depends to some extent on what is available where they live, it is primary determined by the culture (i.e., learned hunting tactics) for each ecotype of orca. For example, one ecotype of orcas in the U.S. Pacific Northwest (called Residents) exclusively eats fish, mainly salmon, and another ecotype in the same area (Transients, or Bigg’s killer whales) primarily eats marine mammals and squid. [Source: NOAA]

orca chasing a chinook salmon

Orcas feeding habits are frequently assessed through looking at stomach contents. They eat a wide variety of large prey including: sea lions, seals, smaller whales, dolphins, fish, sharks, squid, octopi, sea turtles, sea birds, sea otters, river otters, and other animals. Orcas eat about 45 kilograms (100 pounds) of food a day, but they can eat much more than that. They swallow small prey whole, but tend to tear up larger prey before consumption.[Source: Emily Burnett, Animal Diversity Web (ADW) /=]

Orcas are very successful and highly efficient predators.. Like wolves and lions, they are social hunters who often hunt in packs and use coordinated social behavior, precise cooperation among pod members and communication to hunt prey larger than themselves, such as larger whales. They even hunt great white shark and the largest whales. Transient orcas that preying on gray whale calves off Monterey, the California. drown the babies after separating them from their mothers, often after an agonizing struggle. The calves are rich in fat, but the orcas often remove the tongue before dining on blubber.

Orca Mating and Reproduction

Orcas are viviparous, meaning they give birth to live young that developed in the body of the mother, and engage in year-round breeding. Females breed every three to 10 years.Breeding can occur at any time of the year, most often in the summer. The number of offspring is one. twins have only been recorded once The gestation period ranges from 12 to 18 months. The weaning age ranges from 12 to 24 months. Females and males reach sexual maturity at 10 to 13 years. [Source: Emily Burnett, Animal Diversity Web (ADW) /=]

There is no distinct calving season, so birth can take place in any month. The birth rate for orcas are not well understood. Orca cows give birth at very different rates until they are about 40. In some populations, birth rate is estimated at every 5 years for an average period of 25 years. A female that lived to be over 90 had five or six offspring in her lifetime. Orcas, short-finned pilot whales, and humans are the only known species that go through menopause. For a long time it was thought only human females had menopause.[Source: NOAA]

Orcas are polygynandrous; both males and females have multiple mates throughout a season or a lifetime. Among resident orcas, mates are chosen from distantly related pods within their communities in order to avoid inbreeding. As far as anyone knows they don’t mate outside their community. This is at least partly for cultural reasons because different communities speak different dialects and have different traditions and customs.

According to Animal Diversity Web: While orcas are difficult to study in the wild some of their reproductive habits have been recorded and studied in captive whales. Orcas can reproduce whenever females enter estrus, which can occur multiple times a year. However, most breeding happens in the summer, and orcas are typically born in the fall. Female orcas begin to mate between 14 and 15 years of age. The youngest female whale on record to give birth was 11 years old.

Orca Calves and Parenting

Mother and calf

Orca young are precocial. This means they are relatively well-developed when born. During the pre-fertilization, pre-birth, pre-weaning and pre-independence stages provisioning and protecting are done by females. The post-independence period is characterized by the association of offspring with their parents. There is an extended period of juvenile learning. Calves nurse for at least a year. Calves remain in their natal pod after independence.[Source: Emily Burnett, Animal Diversity Web (ADW) /=]

Orcas are cooperative breeders (helpers provide assistance in raising young that are not their own). Because they are not monogamous, it is assumed that the fathers exhibit no parental involvement after mating. When a orca calf is born into a pod, it relies on its mother for nutrition and support. But other members of the pod sometimes help with nurturing tasks.

Orca females invest a lot of energy in raising their offspring. They carry the calf for almost a year and a half, then give birth and nurse for another 12 months. During that time, mothers teach their calves to hunt and include their offspring in the social network of their pods. A gestation length of a year and half was recorded in captivity. Calves nurse for as long as three years, the flow of milk only stops when it is determined that the calf is skilled at catching of prey.

Calves can be 2.2 to 2.4 meters (seven to eight feet) long and weigh nearly 180 kilograms (400 pounds) at birth. They don’t sleep their first month of life. Mothers also stay awake and don’t begin to take short naps until the fourth week after birth. Some studies show that almost half of all newborn calves die before their first birthday. Older mother orcas seem to do a better job raising their young than younger inexperienced ones. A study of 30 years of data by Eric Ward of the Northwest Fisheries Science Center in Seattle found that calves born to older mothers had a 10 percent better chance or survival in the crucial first year of life.

Image Source: Wikimedia Commons, NOAA

Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.

Last Updated June 2023

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