Slashdot linked up this summary of a rather interesting monkey behavior study:

A new study found that male monkeys will give up their juice rewards in order to ogle pictures of female monkey's bottoms. The way the experiment was set up, the act is akin to paying for the images, the researchers say.

The rhesus macaque monkeys also splurged on photos of top-dog counterparts, the high-ranking primates. Maybe that's like you or me buying People magazine.

While the article plays up the "monkeys pay for porn too" angle, I thought it was at least as interesting that they seemed to have an innate sense of economic costs and benefits. Monkeys were willing to "pay" more for what they really wanted, but were also willing to "buy" less desirable objects if they received more "money" (juice) to do so.