A mixed martial arts fighter received an offer of £370,000 to fight a chimpanzee, with a stark warning about life-changing harm.
Cole Johnson said the initial joke became a real fight.
The event appeared to be cancelled after its website went offline over safety and trust.
It was later described as a crypto hoax.
Separately, nine chimpanzees on Ngamba Island chose a baited box on 73 percent of trials when a human pointed, called names, and food-grunted.
By itself, pointing had no such effect.