The killer whales would drive the other whales (usually baleen whales) into the shallow waters of a harbor, where the humans could harpoon them from small boats. The killer whales would signal the arrival of a quarry to the humans by repeatedly breaching and slapping their tails, and then the humans would get in the whaling boats. Once the whale was harpooned and too weak to fight back, the humans first let the killer whales eat their favorite parts -- the tongue and lips -- then towed the rest of the carcass to shore.
When European whalers showed up in the 1800s, the Aboriginals trained them how to collaborate with the killer whales, and the whales adapted to the new whaling style and larger ships of the Europeans. The Europeans called the arrangement "the law of the tongue" after the favorite snack the killer whales always took.
One day one of the European whalers was in a rush and didn't let the killer whales have their customary first bite of the harpooned whale. Once the killer whales saw that the humans had let down their end of the bargain, they never collaborated again.
This story is completely wild, and morally interesting. At the same time, I'm awed by such a complex cross-species collaboration, disgusted at the killer whales for selling out their own kind to human whalers (even though they regularly hunt other whales for food), and impressed at the killer whales for calling off a centuries-long partnership after the humans failed to live up to their end of the bargain.