Close-range vocal interaction in the common marmoset (Callithrix jacchus)

Area of Science:

• Primate vocalization
• Animal communication
• Bioacoustics

Background:

• Vocal turn-taking is crucial in human conversation and observed in some non-human primates.
• Common marmosets (Callithrix jacchus) exhibit antiphonal calling with phee and trill calls.
• Trill calls are common but challenging to study due to low volume and close proximity vocalizations.

Purpose of the Study:

• To investigate the vocal interactions of common marmosets using trill calls.
• To assess the feasibility of using wearable microphones for monitoring primate vocalizations.
• To determine the effect of social context on trill call characteristics.

Main Methods:

• Recording trill calls in captive, pair-housed marmosets using wearable microphones.
• Observing vocal exchanges between partners and with unfamiliar individuals.
• Analyzing call rate, interaction patterns, and spectral properties (fundamental frequency, F0).

Main Results:

• Trill calls were primarily exchanged between partners, not with other animals present.
• Marmosets increased trill call rate and response to partners when outside their home cage compared to strangers.
• The fundamental frequency (F0) of trill calls increased when animals were experimentally separated from their home cage.

Conclusions:

• Wearable audio equipment is effective for monitoring marmoset trill calls.
• Social context significantly influences trill call interactions and acoustic properties.
• Trill calls serve as a vital component of marmoset social communication, sensitive to environmental and social cues.