New Prosocial Behavior in Killer Whales Suggests the Importance of Cultural Traditions in Their Survival
This article was first published on Earth.Org's website - https://earth.org/ on 18 August 2025. Reprinted with permission.
photo by Mike Doherty via Unsplash
New observations highlight the complex social structures and cultural behaviors within killer whale populations.
Killer whales – also known as orcas (Orcinus orca) – are one of the most recognizable mammals in the ocean. These toothed predators grow upwards of 30 feet (9.14 meters) in length and weigh several tons. The adult male’s dorsal fins are approximately 6 feet (1.83 meters) tall, the bodies of individuals bear distinctive black and white markings and as a group, they exhibit highly social behavior.
Ramming Behavior
Recent studies are yielding evidence that groups of whales – also known as pods – display distinctive patterns in what they eat and how they behave. For example, a pod of orcas in the Strait of Gibraltar made global headlines in recent years when young males rammed boats and tore chunks off of the rudders.
An explanation for the whale vandalism has been widely speculative. Lori Marino, President of the Whale Sanctuary Project, suggests that the destructive behavior may have begun as a fad that eventually spread through the group. “The fad, if it continues, can become part of their culture and be passed down from one generation to the next.”
‘Fish Hats’
More benign behaviors in killer whales worldwide have also been reported in recent publications, and seem to indicate cultural learning. One such behavior was first reported in the Puget Sound area some 37 years ago – and was not seen again until last year, when orcas were observed in the waters off Washington State balancing dead fish on their heads.
While the explanation for the behavior remains inconclusive, it demonstrates that unique behaviors are exhibited within pods.
Food Sharing and Mutual Grooming
Other prosocial behaviors are coming to light. In one study published earlier this year, scientists documented instances of wild orca populations distributed worldwide offering various items of food to humans. The authors suggest that offering food items to humans “could simultaneously include opportunities for killer whales to practice learned cultural behavior, explore or play, and in so doing learn about, manipulate or develop relationships with us.”
Food sharing among socially bonded animals is well documented; however, tool use, particularly in marine mammals, is far less common. With the use of drones in a study of resident pods of orca in the Salish Sea off of Washington and British Columbia, researchers witnessed mutual exfoliation or “allokelping” behavior. Whales have been seen in other instances with kelp draped over their bodies, but in this particular study, the whales used the kelp for mutual grooming.
A whale was observed biting off a short section of kelp, balance it on their nose, approach another animal, and then wedge the piece between them before commencing to rub. At first, scientists thought they had witnessed a unique behavior, one-time occurrence but with further examination discovered that it was a widespread behavior within the group. This “allokelping” behavior took place between whales within the same pod, particularly those closely related, of a similar age, or with skin observed to be in need of exfoliation.
“We know killer whales often make contact with other members of their group, touching with their bodies and fins, but using kelp like this might enhance this experience,” Darren Croft, the Executive Director of the Center for Whale Research, told The Guardian.
The resident orcas in the Salish Sea have been closely monitored for more than five decades. The aforementioned behaviors may have been gone unobserved previously due to the absence of drones as a research tool in the study of marine mammals.
Implications of Cultural Behavior on Survival
Future observations may be hampered by external factors such as climate change. By way of example, the rise in sea water temperature threatens the survival of bull kelp (Nereocystis luetkeana), a species that has previously thrived in the cold waters of the Pacific Northwest. It is an annual seaweed that grows quickly, sometimes as much as 10 inches (25.4 cm) in a single day.
The population of killer whales in the Salish Sea currently numbers fewer than 90 individuals. The decline is partly linked to climate change, which is negatively impacting their preferred food source, the king or Chinook salmon. While numerous factors are given for the decline of salmon, one of them relates to ocean conditions that affect their food supply, numbers of predators, and migratory patterns. All these affect the survival of the Chinook and their ability to return to their streams to spawn.
It would appear that cultural traditions play a greater role in the Salish Sea orcas decline because their upbringing has resulted in their reluctance to eat sockeye and pink salmon, which is abundant.