Food sharing is a fairly common behaviour amongst primates - including us humans. After all, the farmer is sharing his crop with you; albeit in exchange for money. Most examples of food sharing fall into this category; with both parties benefiting from the arrangement. A common case is giving another monkey food now, on the understanding they'll return the favour later.
However, humans also share food and do other nice things for each other without any obvious reward. This sort of " prosocial " behaviour seems to be motivated by empathy and appears very early on; with some studies identifying it in children as young as 2. Some studies had identified that chimps, capuchin monkeys and many other primates also engage in this sort of prosocial food-sharing.
For instance, spider monkeys were given the choice of sitting on one of two platforms with food. If they sat on one near to a cage with another spider monkey in; the other monkey also got food. In most cases, they preferred to give the other monkey food as well. However, some researchers have criticised this experiment as the monkey may want to sit nearer its compatriot for other reasons than prosociality. Maybe they're hoping to get some grooming from them.
In fact, these researchers identified these sorts of confounding variables with most of the research into primate prosociality. So they modified them slightly to remove these effects and repeated them. For example, they placed both food platforms near the other monkey. That way, trying to get a back scratch wouldn't bias which platform they picked.
Once they made these modifications they found that the rate of prosociality in the primates they studied dropped off significantly. Chimps, capuchin monkeys, spider monkeys and more were all a lot less keen on "sharing" their food with others. Even when that meant they didn't have to give up any food of their own.
So yes; this counts as another reason to be terrified of the inevitable primate uprising
Reference
Amici, F., Visalberghi, E., & Call, J. (2014). Lack of prosociality in great apes, capuchin monkeys and spider monkeys: convergent evidence from two different food distribution tasks. Proceedings of the Royal Society of London B: Biological Sciences, 281(1793), 20141699.
