Do only humans share with non-kin?
"Comparisons between chimpanzees and humans have led to the hypothesis that only humans voluntarily share their own food with others. However, it is hard to draw conclusions because the food-sharing preferences of our more tolerant relative, the bonobo (Pan paniscus), have never been studied experimentally." write Brian Hare and Suzy Kwetuenda in their article "Bonobos voluntarily share their own food with others" (Current Biology, Vol. 20, Issue 5, R230-R231, 9 March 2010 – available here). They explain: "We gave unrelated bonobos the choice of either monopolizing food or actively sharing: we found that bonobos preferred to release a recipient from an adjacent room and feed together instead of eating all the food alone. Thus, food sharing in bonobos does not depend on kinship or harassment and suggests our own species' propensity for voluntary food sharing is not unique among the apes." And best of all, here is the video: