Humans are known to possess the trait of sharing with others, including strangers. It was thought that sharing is a feature unique to humans developed from social networks, the ability to use language, warfare and/or cooperative breeding.
Now, a new study by researchers from Duke University has found that bonobos, one of the closest relatives to humans, also have an inclination to share with other animals. But, they prefer to share their food with strangers before sharing with an animal they know well, in a bid to extend social interactions.
via (Touch Me!)