A Japanese proverb says, “only when basic needs for living are met can people spare the effort to be polite.” This may be one way that cooperation has evolved. On the other hand, it is also said that cooperation can evolve only when it is necessary for survival. To understand the different ways cooperation can evolve, a comparison of food sharing between bonobos and chimpanzees is both interesting and important.

Exerpt

[...] One of most striking scenes I observed in Wamba was sharing of plant food easily available at the site. On 3 August 2011, I observed Hoshi (a middle-ranking adult female) beg Kiku (a high-ranking adult female) to share pith from Guarea laurentii. After Kiku had chewed some pith like sugarcane to drink its juice, Hoshi took the wadge directly from Kiku’s mouth. When Kiku left, Hoshi stayed in the exact same place and ate fresh pith, already available within arm’s reach. This clearly showed that the begging was not aimed solely at the food itself.
Thus, I hypothesized that (at least some) bonobo food sharing is mainly motivated by the social interaction, and named this “courtesy food sharing,” characterized by begging for social bonds rather than food (Yamamoto and Furuichi 2017).
Consistent with this hypothesis, an investigation of sex and age differences in food sharing revealed that in adults begging occurred predominantly among females rather than males, reflecting the strengths of their social bonds, while in infants and juveniles both sexes demonstrated begging, seemingly targeting the food itself. Among adult females, begging was mostly directed toward dominants from subordinates (including females newly immigrating into the group), further supporting the hypothesis.
In chimpanzees, by contrast, independent individuals (juveniles and adults) sometimes share meat but not plant food. In Bossou, Guinea, chimpanzees sometimes do share crop fruits such as papayas and pineapples, but these fruits are similar to meat in that they are difficult or costly to obtain. Such meat or crop fruit sharing among adults, where the resource is normally controlled by an adult male, is often thought to occur in the context of reciprocity, such as sharing food in exchange for sex. In bonobos, however, such reciprocity has not been identified, neither at Wamba nor at any other bonobo site (such as Lomako and LuiKotale). Even sharing between members of different groups has been observed, both at Wamba and LuiKotale, which certainly cannot be expected in chimpanzees. [...]