There's also the primates that learned to modify sticks (i.e., peal off the bark) to stick in termite mounds, causing the termites to stick to the sap on the wo

There's also the primates that learned to modify sticks (i.e., peal off the bark) to stick in termite mounds, causing the termites to stick to the sap on the wood. This is an invented and learned behavior, but I don't know if there is any cases of a primate teaching another one this trick (vs. a primate picking it up by observation only).