A killer whale was spotted balancing a salmon on its head. It’s not clear what the behavior means, but orcas were observed doing the same thing in the 1980s.

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.

On October 25, an Orca whale from a group of whales called the J pod was spotted with a dead salmon perched on top of its head as it swam through Puget Sound in Washington State, USA. A quick-thinking onlooker snapped a pic and sent it to the Orca Network,

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.