An MMA fighter was offered £370,000 to fight a chimpanzee, with warnings about life-changing harm.
Cole Johnson said the initial joke turned into an actual bout.
The event appeared to be cancelled after its website was taken down over safety and trust.
It was subsequently labelled as a crypto hoax.
In a separate case, nine chimpanzees on Ngamba Island selected a baited box on 73 percent of trials when a human pointed, called names, and food-grunted.
Pointing alone had no such effect.