The Mystery of Orca Trends

July 1, 2023
By Tara Haelle

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Groups of orcas have been seen performing “trendy” behaviors, such as ramming boats, swimming with a dead fish on their nose, and moving shellfish traps. Credit: NOAA

The news was abuzz in June with reports of orcas ramming boats, but this wasn’t the first time groups of killer whales—which are actually members of the dolphin family—have rammed boats. A similar flurry of boat-ramming by orcas occurred in October 2022, for example, though scientists have not yet figured out why these marine mammals are doing this.

But this spurt of boat ramming also isn’t the first time scientists have observed a trend spread among orcas. Over the years, scientists have seen them demonstrate a range of “trendy” group behaviors that reveal just how little we understand about their social structure and culture.

One of the oddest of these occurred in 1987 among the Southern Resident population of killer whales, those off the coast of Northern California, Oregon, Washington, and British Columbia. A single female orca began swimming around with a dead salmon perched on her nose. Before long, several others in the pod began carrying a dead salmon on their noses for the next couple of weeks. Over about six weeks, the trend spread throughout the pod and then, just as suddenly as it started, it stopped. Scientists never figured out why.

Another strange trend was observed in male orcas near British Columbia: they would move around fishermen’s prawn and crab traps even though these shellfish aren’t typically on an orca’s menu. The best scientists could tell, it appeared to be a form of playing, like a game. Unfortunately, the “game”—if that’s what it is—of ramming boat hulls is a dangerous one for both humans and orcas, so hopefully they’ll find less destructive ways of amusing themselves.