Age- and sex-dependent contact call usage in Japanese macaques

Abstract

The question of the flexibility of nonhuman primate vocal communication remains open today, especially due to early evidence of innately guided vocal production. However, socially determined flexibility can be found when the debate is moved from vocal structure to vocal usage. While increasing evidence shows that the audience quality influences the vocal behaviour of nonhuman primates, the impact of the caller's characteristics has been far less studied. Here, we tested the influence of an individual's sex and age on the usage style of contact calls. We recorded contact calls of male and female Japanese macaques and compared the vocal usage styles of approximately 1-year-old juveniles with those of adults at various ages. We found, first, important differences in call usage style between juveniles and adults, the latter forming temporally ruled vocal exchanges respecting an interindividual turntaking principle. Moreover, sex differences were substantial in adults but nonexistent in juveniles. Finally, age continued to influence female vocal behaviour during adulthood, whereas dominance rank explained differences between adult males. Two nonexclusive mechanisms can explain this phenomenon, that is, a socially guided development of the appropriate form of calling versus an emotional maturation to control call emission, opening new lines of research on nonhuman primate vocal development of appropriate usages.

Development in the Usage and Comprehension of Greeting Calls in a Free‐Ranging Group of Japanese Macaques (Macaca fuscata)

“…Juvenile females were less likely to approach or enter grooming interactions upon receiving greeting calls from other individuals than older females (prediction 3‐2, 3), although the responses of vocal replies were not significantly different among age classes (prediction 3‐1), which were clearly shown in a previous study (Lemasson et al. ). Moreover, grooming interactions did not occur more frequently when juveniles were approached with calls compared to without calls, unlike adult and young adult females (prediction 4‐1).…”

Grooming-at-a-distance by exchanging calls in non-human primates

“…Contact calls are produced by most members of a troop in a variety of contexts, but always affiliative [15]. Previous studies on contact calls of Japanese macaques have demonstrated individual recognition [16] as well as exchange rules [15], including turn-taking [17], acoustic matching between callers [18] and persistent waiting for a response [19].…”

Meerkat close calling patterns are linked to sex, social category, season and wind, but not fecal glucocorticoid metabolite concentrations

“…Similar to Japanese macaque contact calls [74], meerkat close calling patterns provided cues with regards to the producer’s sex, age and social rank. Yet, against our expectations, fGCM concentrations did not correlate significantly with tested acoustic parameters.…”