Here is yet another story to remind us how little we understand about orcas, also known as killer whales. We are still scratching our heads over why Iberian orcas attack sailboats near Gibraltar or why orcas off South Africa attack and kill sharks, including great whites, and eat only their livers.
Now, it appears that orcas on the Northwest Pacific coast of North America have started wearing salmon hats again, bringing back a bizarre trend first described in the 1980s.
Live Science reports that scientists and whale watchers last month photographed a 32-year-old male orca known as J27 Blackberry in South Puget Sound and off Point No Point in Washington State swimming with dead fish on his head.
This is the first time orcas donned the bizarre headgear since the summer of 1987, when a trendsetting female West Coast orca kickstarted the behavior for no apparent reason. Within a couple of weeks, the rest of the pod had jumped on the bandwagon and turned salmon corpses into must-have fashion accessories, according to the marine conservation charity ORCA — but it’s unclear whether the same will happen this time around.
The motivation for the salmon hat trend remains a mystery. “Honestly, your guess is as good as mine,” Deborah Giles, an orca researcher at the University of Washington who also heads the science and research teams at the non-profit Wild Orca, told New Scientist.
Salmon hats are a perfect example of what researchers call a “fad” — a behavior initiated by one or two individuals and temporarily picked up by others before it’s abandoned. Back in the 1980s, the trend only lasted a year; by the summer of 1988, dead fish were totally passé and salmon hats disappeared from the West Coast orca population.
Orca researchers’ best guess is that salmon hat fads are linked to high food availability. South Puget Sound is currently teeming with chum salmon (Oncorhynchus keta), and with too much food to eat on the spot, orcas may be saving fish for later by balancing them on their heads, New Scientist reported.
Orcas have been spotted stashing food away in other places, too. “We’ve seen mammal-eating killer whales carry large chunks of food under their pectoral fin, kind of tucked in next to their body,” Giles said. Salmon is probably too small to fit securely under orcas’ pectoral fins, so the marine mammals may have opted for the top of their heads instead.
The food availability theory, however, could be wrong. If the footage reveals that orcas abandon the salmon without eating them, researchers will be sent back to the drawing board.
The salmon hats may have another function altogether. in Northern Australia, male humpback dolphins have been spotted wearing sponge hats in what is believed to be some sort of mating ritual.
Whatever the reason for the behavior, Giles said it’s been fun to watch it come back in style. “It’s been a while since I’ve personally seen it,” she said.
Maybe he was trying to smoke the salmon?