Scientists taught monkeys the concept of money!
Keith Chen and Laurie Santos gave capuchin monkeys a silver piece with a hole and taught them that the coins could be traded for things like fruit. After all the monkeys understood, each one was given 12 coins to spend on items like grapes and Jell-O.
To find out if the monkeys were mindlessly spending, Chen and Santos lowered the price of Jell-O and raised the price of grapes. The monkeys responded by buying more Jell-O and less grapes, just like how humans act with cash.
The monkeys were even taught to gamble and the monkeys made the same choices as a human would! Later on, observers noticed that one of the capuchin monkeys paid another monkey for sex using the specialty coins. Monkeys aren’t so different from us after all.