Orca Feeding, Hunting and Attacks on Seals, Whales and Sharks | Sea Life, Islands and Oceania

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ORCA FEEDING

Orca attacks a seal
Orcas in different places have different prey and different hunting styles. Some corral schooling fish. Others hunt sharks or seals, while some feast almost exclusively on salmon. Killer whale off New Zealand hunts rays. Near Sea Lion Island in the Falklands, they hunt elephant seal pups and sometimes don’t kill the pups right away so young orcas can learn how to hunt them. In Norwegian fjords they chase herring school. These techniques have been deemed partly cultural — learned behaviors passed down through generations. [Source: Craig Welch, National Geographic, April 15, 2021]

According to National Geographic: From the northern Pacific to the seas around Antarctica, killer whales also have varying diets. Some eat sharks, porpoises, penguins, or manta rays. In Patagonia, they launch onto rocky shores and pluck seal pups off the beach. In Antarctica, killer whales flush Weddell seals off floating ice, teaming up to swamp floes and wash dinner into the drink. But the northern and southern residents are both pescatarians, and eat mostly just one species: Chinook salmon.

Some whales see fishing boats as opportunities. In Norwegian waters, killer whales wait for herring to slip from the haul or may pluck fish directly from a net. Killer whales, like fishing boats, follow schools of herring in the Norwegian Arctic. The orcas herd the fish into balls by flashing their underbellies, blowing bubbles, and slapping their tails to stun the fish. Researchers discovered this behavior happens less often when fishing boats are active nearby.

Orcas travel in matrilineal family pods for life and learn how and what to eat within the pod and can become so culturally attached to their food that they won’t switch prey. In 1970, when wild orcas in the Pacific Northwest were still being caught for marine parks, five orcas were driven into a British Columbia cove. Two were taken to a marine park. The remaining three refused to eat the salmon offered by caretakers. One eventually died. Only after 79 days did the survivors start eating fish. [Source: Craig Welch, National Geographic, April 15, 2021]

Craig Welch wrote in National Geographic: The whales were “caught in this behavioral rut”. The caretakers didn’t know killer whales in the Northwest represent three different diets: southern- and northern-resident salmon-eaters; offshore shark-eaters; and Bigg’s killer whales, which hunt only marine mammals. Unlike some other cetaceans whose culture offers them flexibility, these killer whales are unwilling or unable to switch food even when options dwindle, much as Norwegian explorer Roald Amundsen beat Robert Falcon Scott, a Brit, to the South Pole by eating his sled dogs, which Scott refused to do. “It’s just an example of how ingrained these cultures are,” orca expert John Ford says.

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 Hunting Tecniques

Virginia Morell wrote in National Geographic: In the waters of North America’s Pacific Northwest, orcas are divided into three ecotypes based on their diet, which affects the wear on their teeth. Resident orcas live in cohesive family groups and eat mostly fish and squid; their teeth have the least wear. Transient orcas, which roam coastlines in small pods, eat mostly marine mammals; their teeth show large chips and cracks from biting into bone. Offshore orcas travel far out to sea and favor sharks, whose rough skin eventually files down their teeth almost to the gum line. [Source: Virginia Morell, National Geographic July 2015]

There are several orca hunting tactics that some scientists consider to be aspects of the species’ “cultures,” which include strategies for particular kinds of prey. In Argentina, orcas hurl themselves onshore to seize unsuspecting sea lion pups, timing their hunts to coincide with the waves and tides so that they won’t be beached long. In the Antarctic, pod members cooperate to make large waves that wash seals from ice floes. Younger orcas learn these techniques from older ones.

Orcas that specialize in feeding on herring range across the Norwegian and Barents Seas and were estimated at around 3,000 in 1990. About a thousand of them — known as Norwegian orcas — follow herring into the fjords. But herring aren’t predictable prey. Their numbers can vary dramatically from year to year, and they don’t live in the fjords year-round. They spawn along the coast in the spring, disperse into the Norwegian Sea in the summer to feed, and migrate in massive schools in the late autumn to an overwintering area, either off Norway’s coast or in its fjords. Wherever they go, the orcas follow.

Hunting Skills of Transient Orcas

attacking a beaked whale

Transient orcas often kill their prey by ramming them and crushing their thoracic cavity or bludgeoning them with their flukes. They tend to target the weak and often hunt like wolf packs, chasing prey in relays until the prey tires or converging from different directions to corner fast-swimming prey. They also been observed feigning a retreat in one direction, diving and doubling back and catching prey that had let their guard down.

A group of about 300 transient orcas roams primarily around the California coast, but venture as far north as southeast Alaska. They hunt baby gray whales in Monterey during the spring and shift to sea lions, elephant seals and dolphins in the fall. They have also been observed dining on great white sharks, turtles, seabirds and otters. Researchers have documented orca kills of a dog, a pig and even a stray moose and deer caught swimming across inland waterways in the Northwest.

Transient orcas are skilled hunters. It is not uncommon for a pod of transients to enter an area with a healthy population of seals and leave with no seals left. An 11-member pod cleaned out one colony of harbor seals in Puget Sound in matter of weeks, killing a dozen or two dozen a day. In the northern Pacific and southern Alaska, orcas are blamed for wiping out populations of sea lions and fur seals in the 1960s and 1970s and then moving to bigger Stellar sea lions, and causing their population to drop 80 percent from several hundred thousand to 30,000 and then wiped out 50,000 sea otters around the Aleutians. In Antarctica they linked with declines of southern sea lions, southern elephant seals and minke whales.

Strategies of Seal-Eating Orcas

In the Antarctic two orca populations — not subspecies, but different groups that overlap at the margins — used very different hunting techniques, taught across generations. Some Antarctic orcas use the cunning tactic of hunting in packs and making waves to wash seals off floating ice.

In Antarctica transient orcas skyhop to look for seals floating on ice floes. When seals are located various strategies are used to knock them off the floes and attack them in the water. Antarctic transients have been observed creating large waves that wash seals off of ice floes into the water, tilting the ice flows until the seals fall off, or ramming the ice floe hard enough so it breaks apart. In one instance a transient orca was observed leaping onto an ice flow to grab a seal. The whale was then pulled back into the water by two pod members who grabbed the whale by its fluke.

The size of a transient pod is often determined by the size of the prey that the orcas are pursuing. Groups of three or four specialize in young hooded seals, wacking them with their tail and sharing it. Five are six are usually necessary to take down larger, meaner Stellar sea lions, which have large canines that can inflict serious injuries. It often takes orca two hours or more of repeatedly ramming and striking a sea lion with their tails to kill it by drowning.

A group of transients was observed off of Vancouver island killing a minke whale by repeatedly ramming it and finally drowning it by holding it underwater. In Alaska’s Prince William Sound, an orca was observed ramming a Dall’s porpoise and knocking it completely out of the water for a distance of maybe 20 meters. Dolphins have been seen hurtling themselves onto beach rocks to escape from aggressive orcas.

Orcas Kill Baby Sea Lions on the Beaches or Argentina

Peninsula Valdez orca

On the sharply sloping beaches of Patagonia in Argentina orcas sometimes ride waves right on to the beach and beach themselves to capture seal lion pups and even adult elephant seals. Orca mothers teach the technique to their offspring how to beach themselves so can catch seals sunning themselves.

Orcas also aggressively hunt seals off the Argentine coast. Jen Bartelet, one of the first people to record orcas hunting off Patagonia, once noticed a pod of half a dozen orcas patrolling slowly back and forth off of Punto Tombo. "After an hour," she wrote in National Geographic, "the whales shifted to an area just off the tip of the peninsula. Moments later the ocean erupted and the sea lion came hurling out of the water. The other whales moved in, and it was all over in a matter of minutes, with nothing left but scraps of meat on the surface for the kelp gulls to scavenge." [Source: Des and Jen Bartlett March, National Geographic, March 1976]

With their powerful flukes orca have been observed batting a full grown sea lion 20 to 30 feet in the air. "The force of the blow is tremendous," observes Bartlett, "considering that the sea lion may weigh several hundred pounds." The technique stuns the seal lion, making it easier to kill them. Local people have seen whales bat the sea lion several times as if were a "cat toying with a mouse.”Most of the victims are seal pups. "Adult sea lions actually appear to tease the orcas, observed Bartlett. "When the herd knows the whale's location, the adults seem to delight in maintaining just enough distance for safety."

Orca Herring Bait Ball Hunting in Norway

Virginia Morell wrote in National Geographic: “On a cold January day I was surrounded by hundreds of black-and-white orcas streaking like wolves through the waters of Norway’s Andfjorden, 200 miles north of the Arctic Circle. Their backs and tall dorsal fins glistened in the Arctic twilight as they dived and surfaced and worked in teams to corral, stun, and devour silver herring. [Source: Virginia Morell, National Geographic July 2015]

“At times an orca would smack the surface with its tail, as if playing patty-cake with the sea. Orcas make similar tail strikes underwater — death knells for herring, said Tiu Similä, a cetacean biologist who helped pioneer the study of orcas in Norway and is an expert on an orca hunting method called carousel feeding. The force of the blows doesn’t always kill the fish, she said, but it does stun many, making them easy pickings. “What we’re seeing here at the surface only gives a hint of what’s happening below,” she said. “Each whale has a role. It’s like a ballet, so they have to move in a very coordinated way and communicate and make decisions about what to do next.”

“In spite of the numbers of herring, it isn’t easy for the orcas to catch the fish, which are faster swimmers and form defensive, wall-like schools. Orcas can’t just lunge at them and gulp quantities of fish and seawater as baleen whales do. Instead, like sheepdogs working a flock, they herd the schools into tight groups they can control. “The orcas have to stop the fish from diving,” Similä said, “so they force them to the surface and keep them there in a ball by circling around them.”

“Pod members take turns diving beneath the school and looping around it — an orca carousel — while blowing bubbles, calling, and flashing their white bellies to frighten the herring. In response the fish swim even more tightly together. When a carousel is going full tilt, herring leap about on top of the water, desperately trying to escape. “It looks as if the sea is boiling,” Similä said. Once the pod has the herring under control, one orca slams the edge of the school with its tail — serving up dinner.

Humpbacks, Fin Whales and Orcas Carousel Fishing for Herring in Norway

Virginia Morell wrote in National Geographic: Normally the orca pods here fished alone, but on this day humpbacks and fins were swimming among the orcas and eating the herring too. Around us dorsal fins of various shapes and hues broke the water. Orcas shot past, rounding up herring, while humpbacks hurtled skyward, jaws agape, gulping fish before the orcas could pick them off, and the fin whales merely showed their curved fins as they caught a quick breath before sinking back into the depths to feast. [Source: Virginia Morell, National Geographic July 2015]

“Because humpbacks use a method similar to carousel feeding — circling a school of fish or krill, then blowing bubbles to herd them into a ball it is thought they might be cooperating with the orcas. Or the orcas and the whales might be “travel feeding,” simply herding the immense school into a tighter group, then slapping the edge of the herring ball for a quick meal before moving on. “But travel feeding takes more energy than the carousel,” Similä said. “And with so many herring here, a carousel would seem to make more sense.”But the orcas never lingered long enough to carousel feed. They, the humpbacks, and the fins continued to rush past us as if speeding to a gala event, stopping now and then to snack.

On a different day, after seeing orcas spouting on the far side of the fjord, we motored across the two-mile expanse of sea into a calm lagoon. “It’s a whale Eden,” our guide proclaimed as orca pods surged nearby, their dorsal fins riding like sails above the sea, and humpbacks lunged for fish. One pod’s calves playfully surfed in the wake of our boat and then, when the motor was idling, popped up nearby, like prairie dogs, to spy on us. Although these orcas weren’t streaming through the sea, as they’d done on our first day, they still weren’t carousel feeding.

“Similä admired the way each orca had a role in the hunt. She’d seen how adults guided younger ones, how calves imitated their mothers’ tail slapping, how pods sometimes made long journeys to the herring’s spawning grounds, apparently to keep track of the fish. By attaching satellite tags to several of the orcas, she and her colleagues had mapped some scouting missions. “One of the orcas traveled so far and so fast — hundreds of kilometers in one day — we thought he was being pulled away by a ship,” she said. When you’ve spent much of your life around beings that live in cooperative societies, remember their past, and care for their weakest, you learn to be open to what else they might be capable of. So Similä entertained the idea that the orcas had joined with the humpbacks and fins to hunt the fish. “She later changed her mind. “No, they’re not working together,” she told me.“Those humpbacks are just spoiling everything the orcas do. Every time the orcas get the herring organized, the humpbacks wreck it. The fin whales are taking advantage too.”

Orcas Attacking and Killing Whales

Orcas have been observed attacking gray whales, humpbacks, blues, rights, bryde's whales, minkes, sperm whales and other whales. In a survey done off California one third of the humpbacks seen showed what looked like scaring from orcas. Scarring was also seen on blue and gray whales. It is not clear who was responsible: transients or offshore orcas. When it orcas go after larger whales it isn’t clear whether they aim to kill or simply rip off pieces of blubber. The orcas large size and numbers help them ward off rival predators, including pilot whales and a hammerhead shark, from stealing the food.

Off Iceland, a pod of six orcas was observed chasing down much larger whale and eating it alive. Orcas often kill whales that provide more food than they could possibly eat. They have been seen eating the fleshy lips and tongues of minke whales and leaving the animals to die. Once a pair of orcas was observed harassing a large whale and it calf. After six hours they manage to separate and drown the calf. All they ate was the tongue and lower jaw, leaving the rest to sink to ocean floor.

In October 2022, whale watchers spotted an fight between transient orcas and humpback whales off the coast of Washington. The Pacific Whale Watch Association said the fight lasted three hours before the whales disappeared. One of the humpback whales, Hydra, was spotted afterwards in good condition. [Source: Hannah Getahun, Business Insider, October 3, 2022]

Attacks on Blue Whales by Orcas

Thanks to their very large size, blue whales, few natural predators. Blue whale calves are vulnerable to predation by orcas. Sometimes the orcas take adults. sharks. In the 1970s, a group of 30 or so killer whales was observed by a SeaWorld Research vessel attacking a 18-meter (60-foot) blue whale. The orcas attacked from different angles. Some attacked from the front; other came up from behind. Several jumped on the blue whale’s back, in what may have been an attempt to drown it. Others bit off chunks of blubber, After about five hours the killer whales abandoned the attack, perhaps because they were full or maybe because they were tired.

In 2021, 80 orcas took down a 59-foot blue whale. Video showed how the orcas corralled the whale toward the surface, and then in groups of six to eight, they took turns body-slamming the whale and rolling over its blowhole so it couldn't breathe. The hunt took over three hours. [Source: Emily Swaim, Business Insider, May 31, 2023]

Annie Roth wrote in the New York Times: “In March 2019, scientists studying whales near southwestern Australia stumbled on a supersize spectacle that few had seen before — a pod of orcas viciously attacking a blue whale.Over a dozen orcas surrounded the mighty animal. They had already bitten off its dorsal fin, and the animal was unable to evade the fast and agile predators. The water ran red with the blood of the massive creature, and chunks of its flesh were floating all around. The scientists observed one orca force its way into the blue whale’s mouth and feast on its tongue. It took an hour for the orcas to kill the blue whale, and once they did, about 50 other orcas showed up to devour the carcass. [Source: Annie Roth, New York Times, January 30, 2022]

Orca Attacks on Sperm Whales

Describing an orca attack on a pod of sperm whales off the California coast, Robert Pitman and Susan Chivers wrote in Natural History magazine, "Nine sperm whales have gathered to form a “rosette,” their heads pointing to the center, their bodied radiating out like the spokes of a wheel...sperm whales for a ring with their tails out — the out — the tail of a large whale being a formidable weapon." [Source: Robert Pitman and Susan Chivers, Natural History, December 1998]

"One of the [orca] adults charges into the rosset, arches, and broadsides a sperm whale, hitting it hard below the waterline. The wound she inflicts must be serious because fresh blood wells up on the surface of the water...The sperm whales, however continue to hold their formation. Soon four female orcas come charging in, this time from about a quarter mile out. At one hundred yards, they lunge high out of the water, shoulder to shoulder, in synchrony of practiced pack hunters."

"Circling rapidly around the rosette, they stay just beyond the reach of those dangerous tails. One cuts in and locks her jaws onto the side of the sperm whale. We can see flashes of white below the surface as she spins around, tail pumping, trying to wrest a mouthful of flesh. As fresh blood again colors the surface, two more orcas join the attack."

Orca Attacks on Gray Whales

Orcas (killer whales) are the main predators of gray whales. Nearly 18 percent of all gray whales show evidence of orca attack, with juveniles being the most vulnerable. Orca’s hunt in pods and can separate a calf from its mother. Once separated from its mother, the orca pod drowns the calf by holding on to its flippers and tail flukes with their teeth. Adult gray whales often place themselves between their calf and potential predators. When under attack, adults may also swim toward shallow water or kelp beds, where orcas typically do not enter. [Source: Travis Kidd, Animal Diversity Web (ADW) /=]

Attacks on gray whales by an orca pod are savage but efficient, with each orca taking a specific role. Some females are separators, wedging themselves between the gray whale calf and its mother. Some ram the calf with a dull "bang," while others jump on top to drown it. While male orcas can kill a gray whale calf in a couple of hours, a female-led attacks can take up to six hours. Researchers believe this is because the females try to teach their off-spring how to hunt and kill. When a successful kill is made the attackers call in other orcas for a blubbery feast that can last days.

Nancy Black, an independent marine biologist and a co-owner of Monterey Bay Whale Watch, has observed numerous attacks by orcas on gray whales in Monterey Bay. She said, “To avoid detection, gray whales cease noisy, visible spouting and start to “snorkel” — taking quiet, shallow breaths — as they try to sneak across the narrow submarine canyon. If caught, she said the gray whale's best chance is to flee for shoreline shallows, sometimes hiding behind rocks. There, orca teams are unable to surround and subdue the larger prey.

Black said some years crafty orca packs turn the bay into "ambush alley,'' lying in wait for gray whale calves and their mothers to cross the bay's deep-water canyon -- the riskiest stretch of the gray whales 6,000- mile migration from Baja California, Mexico, to their Alaskan feeding grounds. Black uses the whale watching tours to conduct and fund research into lives of orcas that venture year- round into Monterey Bay.

Drone footage taken in March 2023 showed 30 orcas attacking gray whales in the Monterey Bay along the California coastline. Evan Brodsky told KSBW he captured the five-hour battle with a drone from a Monterey Bay Whale Watch boat. The Sacramento Bee reported: More than two dozen Bigg’s killer whales ganged up on the gray whales, which are migrating north, Monterey Bay Whale Watch said on Facebook. Bigg’s orcas, also known as transient killer whales, roam the Pacific Northwest and prefer a diet of marine mammals as opposed to other oras, which eat mainly fish, according to OrcaLab. Monterey Bay is about 120 miles south of San Francisco. [Source: Don Sweeney, Sacramento Bee, April 3, 2023]

The video, posted to Facebook, shows orcas swarming around the whales amid splashes and spouts. “Usually killer whales will hunt gray whale calves as they head up to their northern feeding areas with their moms,” the post read. “But these were not calves: they were huge adult gray whales!” The killer whales eventually broke off the attack when the gray whales split up and headed for shallower water, Monterey Bay Whale Watch said.

Orca Attacks on Gray Whale Calves

In May, 2004 a boatload of whale watchers expecting to see some whales leap out of the water and display their flukes in Monterey Bay, instead witnessed a life-or- death struggle as a pack of six orcas attacked a gray whale calf while its mother valiantly fought to shield her 8-ton baby. [Source: Alan Gathright, San Francisco Chronicle]

Alan Gathright wrote in the San Francisco Chronicle, “As whale watchers looked on with a mixture of awe and sadness, mother orcas — the most experienced hunters — took turns ramming head- first, like 6-ton torpedoes, into the calf's soft underbelly, their force nearly knocking it out of the water, while others leapt atop the 20-foot baby, trying to drown it.” "It's the greatest predation event on Earth,'' said Richard Ternullo, an orca researcher and co-owner of Monterey Bay Whale Watch. "It's 100 tons of whales crashing together.''

“During the 2 1/2-hour assault,” Gathright wrote. “the excited squeals of the orcas... drew others until 17 of the sleek black-and- white super-predators were milling about. To the relief of the spectators, the clash had a happy ending: The 40-ton mother gray whale, rolling like a log to shed attackers and lifting the calf on her back above the attack, led her battered and bleeding baby to shallow coastal waters — where the orcas do not venture.”

But other gray whales have not been as fortunate: About 15 calves were killed by orcas in April and May 2004 in 22 documented attacks. Black said he though 2004 was especially bloody because of a bumper crop of gray whale calves born over the winter. Less ice coverage in the Bering Sea the previous summer allowed gray whale mothers to beef up for their long trip south and produce a bounty of calves in Mexico. "I think the orcas figured out that there were more calves coming through here and alerted other orcas,'' Black said.

Describing a successful attack on a gray whale calf, David Attenburoigh wrote: orcas “detect the approach of a grey whale and her calf [and] fall silent. They start to follow the pair. Before long the whale and her calf become aware they are being chased. The mother increases her speed, encourages her calf to swim as fast as it can, but the killers have no difficulty keeping up. They take turns in harassing the calf. They have to be careful for the female could severely injure them a blow from her tail. After three or four hours, the calf is so exhausted that it can go no further. The killers put themselves between it and its mother. Once it is separated, the killers swim over it, forcing it downwards, preventing it from breathing. Eventually the calf drowns and the killers make their meal.”

South Africa’s Orcas Killing Sharks

In the early 2020s, there were a number of attacks by orcas on sharks, including great white sharks. Mitchell Willetts wrote in the Miami Herald: Eleven sharks washed up dead on a South African beach, their bodies mostly intact but their livers taken, according to researchers. These are some, but not all, of the recent kills made by a pair of orcas known for their prolific hunting and their particular taste for a specific organ. [Source: Mitchell Willetts, Miami Herald, March 3, 2023]

Port and Starboard recently outdid themselves, Marine Dynamics Academy said in a Facebook post. Researchers aboard a Marine Dynamics vessel tracking the orcas witnessed the duo kill 17 sharks in a matter of hours, in waters near the coastal town of Gansbaai, the post said. “We observed the two orcas repeatedly diving down in a small area for almost two hours before they departed offshore,” Ralph Watson, of Marine Dynamics, said.

Several days later, they found the bodies of broadnose sevengill sharks strewn across Pearly Beach, flesh missing where the liver resides. “Each sevengill shark was torn open and missing its liver,” said Alison Towner, a Rhodes University researcher collaborating with Marine Dynamics. The sharks were all female and bore similar wounds to other sharks previously killed by Port and Starboard, Towner added.

“This is the largest amount of sharks these orcas have killed in this area in one sitting,” Towner said. Researchers didn’t say why the orcas killed so many sharks. Or why they were interested in eating their livers specifically, though the organ is nutritious. “The liver of sharks is rich in nutrients and oil, and makes up a large proportion of the shark’s anatomy. It would make sense for orcas to feed on this organ,” Josh McInnes, a researcher at the University of British Columbia, told CBC news in 2022.

Orca Attacks on Great White Shark in South Africa

Orca attacks have likely been one reason — if not the main reason — why great white sharks are seen less frequently in waters around Cape Town, South Africa that before, according to a government report. Library of Congress reported: While the disappearance of great whites had been blamed on illegal hunting and overfishing, the report found that the sharks vanished around the same time two killer whales arrived in the area in 2015. Shark spotters initially reported declines in shark sightings in the area in 2017 when the remains of shark carcasses washed up on beaches. [Source: Sophia Ankel, Business Insider, November 22, 2020]

“Between 2010 and 2016, shark spotters recorded around 205 great white sharks living along the coastal sites of False Bay and Gansbaai, which lie off the eastern shore of Cape Town. However, in 2019 and 2020 only one shark sighting has been confirmed. The report stated the sharks vanished around the same time two killer whales arrived in the area in 2015. The disappearance of great whites had previously been blamed on illegal hunting, climate change, and overfishing

According to the researchers, they "found some evidence for a causative link between the appearances of a pod of orcas that had specialized on preying on white sharks." Two male killer whales, Port and Starboard — named for their collapsed dorsal fins that bend right on one and left on the other — are believed to the main culprits preying on the sharks, often eating only their livers.

Killer Whales Flee Pilot Whales Near Iceland

Killer whales are arguably oceans’ No. 1 predators. But in Iceland, they are known to flee pilot whales. Marina Wang wrote in Hakai Magazine: In 2015, out on the choppy waters off southern Iceland, Filipa Samarra and her research team were eavesdropping on a group of killer whales. She listened as they pipped, squealed, and clicked when suddenly her ears were filled with high-pitched whistling. “Then the killer whales just went silent,” says Samarra, a biologist and lead investigator of the Icelandic Orca Project. As the whistling grew stronger a group of pilot whales came into view, and the killer whales seemed to turn and swim away. “It’s quite unusual because the killer whale is this top predator,” says Anna Selbmann, a doctoral candidate at the University of Iceland who is supervised by Samarra. “It’s very unusual that they’re afraid of anything—or seemingly afraid.”[Source: Marina Wang, Hakai Magazine, Smithsonian magazine, September 27, 2021]

“Interactions between killer and pilot whales have only been scientifically documented a few times, and Samarra is among the first scientists to have observed this behavior in Iceland. Since the 2015 encounter, she’s seen similar interactions around 20 times. Selbmann says in the majority of the interactions documented around Iceland, killer whales seem to avoid pilot whales. Occasionally things will get heated and the pilot whales will chase the killer whales at high speeds, with both species porpoising out of the water. “One of the big questions that we have is understanding the variability,” says Samarra. “We don’t really understand what are the contextual factors that drive their response being different sometimes.”

Orca “Adopts” a Baby Pilot Whale — First Known Case of its Kind

In the early 2020s, a female orca was observed caring for a baby pilot whale. The orca appeared to have adopted baby pilot whale in the first known case of its kind. Business Insider reported: The orca, known as "Sædís," was first observed swimming with the pilot whale calf in August 2021 in western Iceland. Scientists observed that Sædís was not simply accompanying the calf but was actively caring for it. Two other orcas, likely from Sædís' pod, were also present, but no other pilot whales were seen — which is unusual because pilot whales also travel in pods. This marks the first scientific documentation of orcas nurturing and tending to a long-finned pilot whale calf. [Source: Alia Shoaib, Business Insider, February 25, 2023]

The findings recently published in the Canadian Journal of Zoology document the orca's maternal care for a pilot whale calf and suggest that the relationship between the two species is more complex than previously thought. Marie Mrusczok, the lead author, told Newsweek that there were clear signs the orca was looking after the calf. "The orca was swimming with the pilot whale calf in the echelon position, which means the calf was swimming right behind the pectoral fin of the orca," she said. "The echelon position allows a calf to make fewer tail fluke movements than when swimming on its own and overcome physical limitations during high-speed travel — in other words, the calf is 'carried' by the pressure wave created by the adult's larger body."

However, Elizabeth Zwamborn, an academic on the research team, told the Canadian Broadcasting Corporation's Maritime Noon show that it was unclear whether it was an altruistic adoption. She said the relationship could be interpreted as a "lovely warm adoption story" or a case of orca abduction. "But there's also a decent chance that she actually abducted this calf from a group of pilot whales. Off Iceland, there's been quite the interaction between both species, and oftentimes pilot whales are seen chasing the orcas," she said. "We don't know the reasons for it, but if there's a chance that there might be a female orca here and there that tries to take a calf from the pilot whales, that would certainly give them reason to chase."

The study noted that Sædís had never had a calf of her own, so it is possible she took in the pilot whale calf as a substitute. Zwamborn said that the calf appeared to be emaciated and seemed to have not been fed recently, which would make sense as the female orca would probably not be able to nurse, having not birthed her own calves. Both orcas and pilot whales have similarly close-knit family structures in the wild, which could explain the relationship. About a year later, Sædís was observed with a group of long-finned pilot whales, but the calf was not present. Further encounters between Sædís' and the pilot whale pod indicated a deliberate attempt to acquire a new calf, the findings said. Zwamborn told CBC that Sædís' observed interactions with pilot whales appeared to be unique and that she could have been attempting to abduct another calf.

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