If it helps, that's not monkeys inventing capitalism, it's monkeys responding to a system of currency that was enforced on them by scientists. That's a very different thing.
Essentially what they've discovered is an example of the logic of capitalism reproducing itself within those it subjugates.
Don't bonobos offer sex for services or food in the wild? Still not necessarily capitalism to have a market, unless there was a bonobo pimp exploiting bonono hookers to profit off them without doing a damn thing himself.
If they did it still wouldn't be capitalism. Capitalism isn't just when market, and I don't know why it's important that sex is the thing being offered except to make it sound worse because our society hates sex workers.
Fair, it just seems like the people using this example are leaning hard into the "prostitution" angle. I didn't mean to imply you were bringing it up because you personally hate sex workers or anything.