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.
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.