Responses toward a trapped animal by wild bonobos at Wamba

Abstract

Chimpanzees and bonobos are the closest living relatives of humans and diverged relatively recently in their phylogenetic history. However, a number of reports have suggested behavioral discrepancies between the two Pan species, such as more cooperative and tolerant social interaction and poorer tool-using repertoires in bonobos. Concerning hunting behavior and meat consumption, recent studies from the field have confirmed both behaviors not only in chimpanzees but also in bonobos. The present study reports an encounter by wild bonobos at Wamba with a duiker trapped in a snare. Bonobos interacted with the live duiker for about 10 min but did not eventually kill the animal. They showed fear responses when the duiker moved and exhibited behaviors related to anxiety and stress such as branch-drag displays and self-scratching. Although bonobos manipulated nearby saplings and parts of the snare, they did not use detached objects to make indirect contact with the duiker. Juveniles and adults of both sexes engaged in active interactions with the trapped duiker. Overall, bonobos' behavioral responses indicated species-specific cognitive characteristics largely different from those of chimpanzees.

<Note>Non-lethal handling of a captured duiker by a bonobo (Pan paniscus) at Wamba: Implications for prey image in bonobos

“…Bonobos at Wamba have been observed in non-lethal interactions with other primates, including mutual grooming between bonobos and red colobus (Colobus badius) (Ihobe 1990) and a bonobo carrying the corpse of a redtailed monkey (Toda et al 2017). In addition, there was a single previous report of bonobos interacting with, but not killing or eating, a trapped blue duiker (e.g., approaching, sniffing, touching) (Hayashi et al 2012). Multiple similar incidents have been observed in the habituated groups at Wamba (N. Tokuyama, personal observation; T. Yokoyama, personal observation).…”

“…There was no blood or duiker fur around her mouth, on her hands, or on her body. During the observations, I did not hear any specific bonobo vocalizations expressing anxiety, stress, or social tension (Hayashi et al 2012;Yokoyama & Yasumoto 2019).…”

<Note>Behavioral responses toward a conspecific corpse of wild bonobos (Pan paniscus) at Wamba

“…We should carefully consider the differences in how bonobos react to the corpses of conspecifics and other animals. Bonobos have been observed to approach, peer, sniff and carry the corpse of other animals, as well as returning repeatedly to the same location (Hayashi et al 2012;Toda et al 2017;Tokuyama, personal communication). Wild chimpanzees have also been reported to interact with the corpses of other animals (van Lawick-Goodall 1968;Boesch & Boesch-Achermann 2000).…”

<NOTE>Snare-related disability led to the near-fatal accident of a bonobo at Wamba, Democratic Republic of the Congo

“…Bonobos sometimes gather around trapped animals, dugout canoes that local people make in the forest, and so on. In such cases, bonobos often approach, peer, touch, and shake branches toward the objects (Hayashi et al 2012;N Tokuyama personal observation). Bonobos also sometimes re-visit the place of an unusual event after a few hours or days (N Tokuyama personal observations).…”