One behavioural economist who works with primates says that his experiments make the monkeys “statistically indistinguishable from most stock-market investors.” Some of the things he has found include:

• Monkeys were trained to use money. They demonstrated a healthy knowledge of the laws of demand, substitution, and utility maximization. When prices for one good went up, they bought more of other, substitute goods.
• One monkey managed to set up a bank heist and a jail break and escaped with a lot of the tokens the experimenters were using for money. Whereas the currency had been contained in a controlled environment up until then, once the money was freely available to all of the monkeys in the cage with no rules about what they could spend it on, chaos ensued.
• One male monkey gave a token to a female monkey, and then had sex with her. The female monkey used the money to buy food. This is thought to be the first case of money being exchanged for sex in a non-human species. In other words it is the first recorded case of non-human prostitution.

To read more about the similarities between humans and monkeys, why selfless and selfish monkeys face similar outcomes, and the irrational behaviours decisions that both monkeys and humans make click here.

Source: The New York Times