Off the coast of Washington State, orcas have started wearing salmon hats again. The trend was first described in the 1980s. But last month, it appeared that the behavior was in style once more.
Orcas in South Puget Sound and Point No Point in Washington State were spotted swimming with dead fish on their heads. The last time they donned such gruesome headgear was in the summer of 1987.
A female orca from the West Coast was the trendsetter. After a couple of weeks, the rest of her pod were wearing salmon corpses as well. The orcas sporting salmon hats now may have experienced the trend when it first began almost 40 years ago.
“It does seem possible that some individuals that experienced [the behavior] the first time around may have started it again,” said Andrew Foote, an evolutionary ecologist at the University of Oslo in Norway.
There does not appear to be any reason for the development of salmon hats. Perhaps the hat-wearers were trying to impress another member of their pod, or they simply liked the smell of dead fish.
The salmon hats are what researchers refer to as a “fad.” One or two individuals might start engaging in a behavior that is picked up by others until it is eventually abandoned.
The salmon hat trend of the 1980s only lasted for a year. By the summer of 1988, the West Coast orca population was no longer wearing dead fish as hats.
According to researchers, the salmon hats may be associated with high food availability. Currently, South Puget Sound is filled with chum salmon.
The orcas could be wearing the fish on their heads to save them for later since there is too much food to eat all at once. Orcas have also been observed to stash food in other places.
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“We’ve seen mammal-eating killer whales carry large chunks of food under their pectoral fin, kind of tucked in next to their body,” said Deborah Giles, an orca researcher at the University of Washington.
It is possible that salmon is too small for the orcas to fit securely under their pectoral fins, so the marine mammals may have chosen to wear them on their heads instead.
In 2005, southern resident killer whales were listed as endangered due to a lack of food. So, the salmon hat sightings can be interpreted as positive news from an orca population that had been struggling.
Now, drones equipped with cameras can monitor the orcas and study their behavior more thoroughly. Such a feat was not achievable 37 years ago.
After some time, the researchers might be able to figure out if orcas carried fish for a while and then ate the fish when they got hungry.
But if the drone footage shows the orcas abandoning the salmon without eating it, they will need to come up with a new theory for the bizarre behavior.