Basic primate behavior. I had a friend who was a comparative psychologist and worked for the local zoo. I went to visit her and she took me behind the scenes. We observed the chimps from behind their enclosure. She said watch this one. He would surreptitiously poop in his hand and put it behind his back. He would walk to the front of his cage and then do a funny dance to attract a crowd. When it assembled, he would leap into the air and slam dunk the poop at them. Scoring direct hits on Mommys and babies in little strollers. They seemed to be his preferred target.

I supposed the Zoo staff might have taken preventive measures but they got a kick out of it.