A pod of killer whales has revived a curious trend from the 1980s in which they swim around with dead salmon balanced on their heads.

Though researchers have some best guesses, nobody seems to know for sure why exactly a killer whale in Washington state was wearing a dead fish as a hat.

Sometimes, nature surprises us with behavior that feels more like a quirky human trend than an animal instinct. That’s exactly what’s happening off the Pacific Northwest coast, where orcas are once again donning “hats” made from dead salmon.