7 research outputs found
Differential behavioural effects of silent bared teeth display and relaxed open mouth display in chimpanzees (Pan troglodytes)
This study examines the behavioural consequences of the silent bared teeth display (SBT) and the relaxed open mouth display (ROM) in the chimpanzee, and discusses functional similarities with smiling and laughing (respectively) in humans. Rates of affinitive behaviour increase (in relation to baseline levels) following SBT, suggesting that SBT is a signal of affinity. ROM is observed primarily during play, and dyadic play bouts are significantly longer when ROM is bidirectional, indicating that it may be a signal of play. Rates of affinitive behaviour also increased after ROM, suggesting that both displays may have a similar ultimate (evolutionary) function - social bonding; this could explain convergence of the two displays in humans
Not here, there! Possible referential gesturing during allogrooming by wild bonnet macaques, Macaca radiata
Intentional referential gestures, a fundamental
building block of symbolic human language, have been
reported from a range of species, including non-human
primates. While apes are known to spontaneously use
intentional gestures, only captive macaques, amongst nonape
primates, appear to intentionally display learnt gestures.
On the other hand, referential gestures have so far
been reported only in chimpanzees, amongst non-human
primates. We document here, for the first time, potentially
referential gesturing, used intentionally as well, in a monkey
species, the bonnet macaque Macaca radiata, in the
wild. Bonnet macaques use four distinct actions during
allogrooming, possibly to indicate a particular body part
intended to be groomed. These acts were successful in
drawing the recipients’ attention to the indicated part,
which they began to groom subsequently. This study
enriches our understanding of non-ape primate gestural
communication and adds to the growing evidence for early
human language-like capacities in non-human species