Fair trade

The world's oldest profession just got older.
Even chimpanzee's trade goods for sex--

"Daring behavior certainly seems to be an attractive trait, and possessing a sought-after food item, such as papaya, appears to draw even more positive attention from the females."
Males especially chose to share food with a preferred female, one who took part in the most "consortships"—where she spent time alone with a male so he got an exclusive chance at sex.