Pre-Feeding Reassurance in Bonobos and Chimpanzees: Touch as a Catalyst for Peaceful Cooperation

The Conversation: Ape consolation and social touch

Researchers conducted an eight-month study of bonobos in the Democratic Republic of Congo and chimpanzees in Zambia, observing that friendly physical contact—embraces, pats and kisses—clusters in the minutes before a feeding task begins, even before distress signals emerge. This pre-emptive reassurance, observed during the peanut swing task, correlates with more peaceful cofeeding afterwards, implying touch helps manage social tension and maintain tolerance. The findings from Lola ya Bonobo and Chimfunshi sanctuaries point to deep evolutionary roots of social bonding shared with humans and other apes.

• Pre-emptive touch correlates with peaceful feeding post-anticipation
• Patterns align with social structures: female alliances in bonobos, male reassurance in chimpanzees
• Tolerance underpins cooperation and social learning across species
• Touch before competition may signal trust and intent

Author: The Conversation.

Overview

During an eight-month field study in the Democratic Republic of Congo and Zambia, researchers followed bonobos and chimpanzees as they navigated typical social competition around a tree laden with ripe fruit. They noticed a surprising pattern: friendly physical contact—embraces, pats and kisses—often accompanied interactions before any explicit conflict or distress signals emerged. The team questioned whether such touching serves a function beyond mere social bonding, particularly in tense moments of anticipation when food is about to become available.

The article situates these observations within a broader question about how primates manage social stress and how such early reassurance touch could contribute to tolerance, a foundational element of cooperation and social learning across species including humans.

Methods

Colleague Edwin van Leeuwen developed a feeding task known as the peanut swing to measure social tolerance in great apes. The setup fills a bamboo trough with peanuts and swings it over a fence so the food lands before the apes, spreading peanuts evenly across a defined space. Researchers filmed 116 individuals across five groups at two sanctuaries—Lola ya Bonobo in the DRC and Chimfunshi in Zambia—and conducted 60 sessions to observe a five-minute anticipation period before the food release. They tracked friendly touch such as kissing, embracing and gentle contact, as well as aggression and threats, to quantify how anticipation relates to subsequent peaceful cofeeding and the tolerance patterns of each group.

Findings

Across both bonobos and chimpanzees, those individuals engaging in more reassuring touch before feeding spent more time feeding peacefully alongside others afterwards. The pattern persisted across most groups and was strongest within the more tolerant groups. Bonobos showed a gendered pattern consistent with their social structure, with female–female reassurance being most frequent, while in chimpanzees, reassurance was most common among males, reflecting their social organization. In groups with more authoritarian leadership, the pre-emptive touch pattern tended to disappear, suggesting leadership style modulates the use of touch to maintain tolerance.

Interpretation

The researchers propose that the vulnerability involved in risky contact—placing fingers or body parts inside another’s mouth, or touching genitals in tense moments—may itself be a trust signal. Offering such touch could reflect confidence in the partner’s restraint and in the bond between individuals. This interpretation links the immediate behavior to broader themes of social cognition, cooperation and social learning, and aligns with the view that touch is an ancient channel of communication that predates language.

Broader context

Beyond apes, the article connects these patterns to human research showing that touch can reduce anxiety after witnessing or experiencing conflict, and that supportive touch after distress can mirror consolatory actions seen in chimpanzees. The authors emphasize the deep evolutionary roots of reassuring touch and suggest that pre-emptive contact before competition is a potential mechanism for sustaining cooperative behavior across species.

Conclusion

These findings support the idea that reassuring touch predates humans and likely existed in our last common ancestor with bonobos and chimpanzees. By showing how anticipatory social contact relates to cooperative feeding, the study highlights a fundamental, ancient behavior that can help maintain peace within social groups, and invites reflection on how touch shapes social life across species.