Category: animal behavior

Intentional Stranding in Wild Killer Whales vs…

One topic I have been pondering lately is the issue of captive killer whales intentionally stranding themselves on slide-outs in marine parks. It’s often cited as an abnormal, stereotypical, and or/dangerous behavior by those against captivity and viewed as normal by those in favor of it. Typical online debates around this issue usually go the following way:

1. Video or photo of a captive killer whale intentionally stranding on a slide-out is posted. 

2. Somebody claims the behavior is unnatural and dangerous. 

3. Another person refutes this, citing populations of killer whales in the wild that use intentional stranding as a hunting method. 

4. Someone points out captive killer whales are not from these populations, therefore, it is not natural and a sign of abnormal behavior in captivity. 

I do not support killer whale captivity myself, and I used to believe with certainty that intentional stranding by captive killer whales was absolutely evidence that captivity altered their normal behaviors. Over the course of my marine biology degree, I’ve had the opportunity to study killer whales, both through the literature and with personal observations in the wild. One thing I’ve learned is that their behavior is often far more complex than we think and when it comes to judging whether or not a behavior is “abnormal” in captivity, a lot more scrutiny and critical thought is required than is typically given. I think the topic of intentional stranding is one of those things that may require a closer look. 

In the Wild

In the wild, two populations of killer whales are known to intentionally strand on beaches: the killer whales around Punta Norte in Argentina and those in the Crozet Islands.

Female killer whale stranding to catch a southern elephant seal in Punta Norte. Photo: Wildlife Trails. 

In Argentina, both adult males, adult females, and juveniles will intentionally strand on the sloping beaches in order to capture southern elephant seals and South American sea lion pups. In some cases, stranded adults have been observed capturing sea lions and then “flinging” them over to stranded juveniles, apparently in an attempt to teach them how to hunt.  

In the Crozet Island, two forms of intentional stranding have been documented, one that involves strand hunting for elephant seals and another known as “social stranding play,” in which adult females, calves, and juveniles intentionally strand themselves in non-hunting contexts. This stranding play behavior may occur in adult females as a way to further refine their hunting techniques, or it may be for social purposes, such as establishing social standings/dominance within a group. In contrast to Punta Norte, male killer whales do not strand-hunt in the Crozet Islands, likely due to their large size and high risk of becoming stuck. 

In Captivity

Slide-outs are raised platforms within killer whale tanks, typically covered in a shallow amount of water. They are frequently used in shows and for husbandry activities that require whales to be out of the water for a procedure, such as taking urine samples. 

Katina on a slide-out in SeaWorld Orlando. Photo: The Dolphin Project

Captive killer whales have been observed to intentionally strand themselves on slide-outs outside of husbandry or show contexts. In the video below, Makani, a juvenile male, voluntarily strands himself on a slide-out: 

When videos like this are posted online, they are often met with backlash. One of the most common arguments is that stranding in captive killer whales is entirely “unnatural” because no captive killer whale originates from either the Punta Norte or Crozet Island populations. Usually, this is followed by the assertion that their bodies are not adapted to be out of the water on slide-outs. However, we must think critically about this. There is currently no evidence that either the Punta Norte or Crozet Island killer whales are more physiologically adapted to stranding than any other killer whales, including captive ones. I see no reason why it would be more dangerous for a captive killer whale to intentionally strand than a wild killer whale. 

It seems strand hunting and stranding play techniques are cultural. Culture, which is defined as “information or behavior—shared within a community—which is acquired from conspecifics through some form of social learning,” is very prevalent in killer whale populations around the world. The strand hunting techniques in wild killer whales are likely not instinctual––rather, they are probably cultural and learned as calves, passed down from mother to offspring and learned from observation or direct teaching. There does not seem to be any reason other populations of killer whales could not learn to display similar hunting techniques if provided the right environment, including captive killer whales. 

I don’t think many people consider that captive killer whales are likely capable of cultural learning as well. While they live in a radically different environment than wild whales, they are still killer whales with the same brains and learning capabilities. Perhaps strand hunting in wild killer whales got its start when an intrepid individual hastily and successfully chased and captured a sea lion on a beach. Perhaps it shared this information with its conspecifics, and the behavior spread throughout the population, eventually morphing into play behavior (or perhaps the other way around?). In captivity, this behavior started with a human trainer teaching the whales how to slide-out, and the whales subsequently have taught other whales to do so. At this point, many people will say “But it’s unnatural!”, but from what I have watched in some videos, it is not so fundamentally different than what is occurring in wild killer whale populations. In the video below, Wikie, an adult female, is seen pushing her son Keijo onto a slide-out and is accompanied by her other son, Moana: 

Note how she repeatedly pushes her calf onto the slide-out, and then backs off as he figures out how to get off on his own. This is similar to what has been observed by Guinet (1991) in the Crozet Island killer whales

“I also observed, in calm sea conditions, female A3
pushing her calf, A5, with her head to strand it. She then
stranded farther onshore, in front of her calf, so that she could
assist it in returning to deep water. The adult females were
always observed returning to the water from the shore at the side
of the calf, apparently to help it roll back into the water.”

Here, Wikie does not strand on the slide-out with Keijo, rather, she waits in the water for him to return before pushing him back up. Some have interpreted her behavior as malicious, as trying to permanently strand him to kill him. I do not see an aggressive, infanticidal animal in this video: I see a mother teaching her calf how to strand on a slide-out, which seems strengthened by the fact her mother, Sharkan, was known to do this to her as well. 

Stranding may be a behavior that was taught to captive killer whales by humans, but it seems as if they have incorporated it into their behavioral repertoires on their own. A behavior that originates with humans is not necessarily bad or harmful to the animals. For example, tail-walking is a common behavior taught to captive dolphins, but it is absent in the wild except in one special population. Billie, a wild bottlenose dolphin, was brought into rehab for a brief stint in Australia after being trapped in a local harbor. She was never trained to tail-walk, but was kept with dolphins which were. When she was released back into the wild, she displayed this tail-walking behavior and it rapidly spread throughout her population despite the fact it was a behavior that originated with humans in captivity. A perfect example of cultural learning. 

I think perhaps this is what occurs with intentional stranding in captive killer whales as well. That said, there are some instances where stranding on the slide-outs may have negative implications, such as if it becomes a repetitive behavior or when an animal gets stuck.

It is important to view the behavior of captive killer whales through a critical lens and understand the contexts and the roots of the behavior before we jump the conclusion of “it’s unnatural, so it must be bad.” Killer whales are amazingly complex and intelligent––what plays out in the wild may also be occurring in captivity, just in a very different way.

Killer Whale Births Observed in the Wild

Killer Whale Births Observed in the Wild

It is very rare to observe a wild killer whale birth, but it has happened on two occasions. 

On July 11th, 1990, researchers were observing the L8 subpod in Juan de Fuca Strait off Victoria, British Columbia. The whales, part of the southern resident population, had been traveling at a normal and steady pace when their behavior suddenly changed. They turned around, heading back toward the direction in which they had came from and began milling about, with occasional high-speed movements and splashing. One whale then displayed an unusual “rotating” behavior, which has never been observed outside of this context. After a few more rotations, three whales spy-hopped in unison with a tiny newborn calf balanced on their rostrums. This calf was L82 Kasatka, pictured above (Photo by Melissa Pinnow, SanJuanOrcas.)

The whales then began circling clockwise for roughly 10 minutes, with the infant wedged in between L55 Nugget, the presumed mother, and L27 Ophelia. Once the circling stopped, the newborn was in the center of the circle, and high-energy behaviors suddenly began. There was splashing, lobtailing, and the newborn calf was lifted up by the whale. She was even thrown about three-quarters of the way out of the water by the other whales. The adults frequently surfaced underneath her, lifting her up out of the water on their bellies. They lobtailed on top of her, and were displaying percussive behaviors that were described as “almost aggressive in nature” by the researchers. Additionally, the researchers concluded that these types of behaviors directed to a newborn would likely be very stressful. Similar behaviors were documented a few years earlier by another researcher who observed a live birth in a northern resident killer whale pod. 

While live births have not been observed since this incident, these intense and borderline aggressive behaviors towards newborn calves have been noted by naturalists working on whale watching vessels. The newest member of the southern resident population, L124, was also subjected to this strange behavior. Naturalists witnessed L124 being “tail-slapped” out of the water and rough-housed by adult whales. 

There is currently no explanation as to why these resident killer whales seem to occasionally subject their newborn calves to extremely rough behavior. Because births are rarely ever witnessed and we can only see what is going on when the whales are at the surface, it is difficult to make any solid conclusions.  


Stacey P.J., and Baird, R.W. 1997. Birth of a resident killer whale off Victoria, British Columbia, Canada. Mar. Mamm. Sci. 13:504-8. LINK

When Transient Killer Whales Meet Resident Kil…

In the Pacific Northwest, there are two kinds of killer whales that have overlapping ranges: residents and transients. Each is a distinct ecotype (and considered sub-species by many) that differ in morphology, coloration, behavior, vocalizations, genetics, and prey type. Transients subsist off of marine mammals such as seals, sea lions, and porpoises, while residents eat exclusively fish, mainly salmon. These two populations don’t interbreed with one another. However, they do live in the same region and have plenty of opportunities to stumble upon each other. 

What happens when a group of transient killer whales and a group of resident killer whales come in contact?

For the most part, they seem to prefer to avoid each other. When residents and transients come within a few kilometers and are on a course to intersect, transients will typically peel away and change their direction to avoid coming in contact with residents. Because residents tend to be “chatty” and travel in big groups, it is assumed that transients––which are quiet and stealthy to avoid alerting potential prey to their presence––hear the residents and slink off before the residents are even aware of them. Less often, residents have changed course to avoid transients. 

There is one case, however, where things did not go so cordially. In 1993, a nasty spat was observed for the first time between residents and transients. Graeme Ellis, a researcher with the Pacific Biological Station in Nanaimo, Canada, had gone out to document some killer whales he had been notified of. It was a few members of J pod, a group of residents belonging to the southern resident population. They were racing towards Gabriola Island, where they met up with the rest of J pod. According to Ellis, the whales were extremely agitated, splashing and racing towards Descano Bay in a large, tight group. It soon became evident that J pod were not the only whales present there––three transient killer whales, T20, T21, and T22, were about 100 yards in front of them. 

T20 and T21, two of the three transients involved in the J pod attack. Photo by Five Star Whale Watching.

J pod closed in on the transients, apparently trying to push them against the rocky shoreline. The water was soon boiling with the commotion of 20 very irritated, aggressive whales. Ellis reported hearing intense squeaks, clicks, and whistles through the hull of his boat. There was whale-on-whale contact with biting and pushing and jostling. Eventually the clash ended, and the transients high-tailed it away from the J pod whales, which were still huffing and circling the bay. When Graeme went over to check out the transients, he noticed fresh cuts and rake marks. J pod, on the other hand? Not a single new scratch on any of the whales. After J pod had calmed down, Graeme noticed three whales were absent: J17, her new baby J28, and grandmother J5. 

J28 in 1993 with her mother, J17. Photo by Ken Balcomb, Center for Whale Research. 

The absence of this newborn calf and her immediate relatives from the proximity of the attack seems to suggest that J pod did not want this new baby near the transients. In 2016, transients were observed partaking in infanticide––the killing of an infant––for the first time. Perhaps residents perceive transients as a threat to their calves. However, it is all speculation because this encounter between J pod and the T20s remains the only aggressive incident ever observed in over 4 decades of killer whale field research in the North Pacific and its cause still remains a mystery. 


Baird, R.W. and Dill, L.M. (1995) Occurrence and behaviour of transient
killer whales: seasonal and pod-specific
variability, foraging behaviour, and prey
handling. Can. J. Zool. 73: 1300-1311. 

Howard Garrett:

chalkandwater: Sleeping sperm whales Blue Plan…


Sleeping sperm whales

Blue Planet II (Episode 4: Big Blue, 2017)

cedorsey:© Video Credit Baby whales don’t know…


© Video Credit

Baby whales don’t know how to breathe, so their mothers have to hold them up, close to the surface, until they learn. 

essenceofnatvre: planetearthtv Every year, one…



Every year, one of the largest migrations in the world happens off the east coast of South Africa, the sardine run. Reports from spotter planes have mentioned shoals as big as 7 km long and 1.5 km wide (4.3 x .9 mi), usually accompanied by dolphins in their thousands. Here a baleen whale takes its turn on the banquet.

🎥 & Caption by @oceanx @brocqmaxey

Bryde’s Whale fun fact: when swimming, they may abruptly change direction, for no apparent reason. Their breathing pattern is irregular too. Science has no explanation for Bryde’s whales being the way they are.

bogleech: apparently one whale years ago was …


apparently one whale years ago was observed doing this for hours and now more and more whales in the area are seen copying it so we think it’s a whole new behavior and it seems to be a response to shrinking food sources.

Instead of expending any energy actively hunting, the whale just holds its mouth open wherever fish are being hunted by birds. To escape the birds, the fish try to hide in the whale’s mouth because it’s a darker area that looks like shelter.

…They’re turning into giant, sea-mammal pitcher plants.

Do aquatic mammals have eyelids? Or are their …

Do aquatic mammals have eyelids? Or are their eyes more like fish so they never close?

They do! I’m gonna talk about dolphins and whales because, as cute as the eyes of other aquatic mammals may be, I don’t know much about them. 

Unlike ours, the eyelids of cetaceans are chubby, they are really thick, but that’s no issue to them, because they don’t close them often. They don’t need to blink as much as we do. When they do blink, they spread these jelly-like tears all over the eyes to protect them. The tears are so viscous they can cover the eye for a long time. 

They shut their eyelids when they sleep as well, but in that case they tend to only close one eye. Whales and dolphins only sleep with one half of the brain, while the other half stays awake. They keep one eye open, so they can stare deep into your soul even while they nap.


Gray Whale eye by Tarnya Hall

Pregnant humpback whale taking a nap 💙 Clark …

Pregnant humpback whale taking a nap 💙 Clark Little

last-tambourine:Photo by Franco Banfi Synchron…


Photo by Franco Banfi
Synchronized Sleepers, sperm whales
Caribbean Sea