One obvious example of these fads is the dead salmon hat trend of 1987. In the Puget Sound area of the northeast Pacific, one female orca from k-pod began carrying a dead salmon around on her nose. Over the next five to six weeks, the behavior spread, and by the end of it, orcas from her own and two other pods were wearing dead salmon hats.
"Observations indicate they are likely finding plenty of salmon during their stay and may be why they have remained inland so long," the whale sighting network reports, adding, "check out this photo of J27 Blackberry sporting a salmon hat."
As yet, we still don't know why orca perform this behavior. It could be that some of the orca were around during the last salmon hat phase, and are bringing it back while salmon supplies are plentiful. One idea, highlighted by New Scientist, is that they are simply using their head as storage space, saving excess salmon caught during salmon abundance for later consumption. Maybe it's less of a salmon hat trend, and more a case of using their head as a lunchbox.
"oh here comes Gladys again wearing that wretched salmon hat thing"