Dialects in pygmy marmosets? Population variation in call structure

Area of Science:

• Primate ethology
• Bioacoustics
• Neotropical mammalogy

Background:

• Population variation in primate vocalizations is infrequently documented.
• Understanding vocal differences is crucial for primate communication studies.

Purpose of the Study:

• To investigate population-level variations in vocalizations of wild pygmy marmosets (Callithrix (Cebuella) pygmaea pygmaea).
• To identify potential drivers of interpopulation vocal differences in this primate species.

Main Methods:

• Acoustic analysis of Trills and J calls from 14 groups across five populations in Ecuador.
• Discriminant function analysis to classify calls by population of origin.

Main Results:

• Significant population-specific structural differences were found in both Trills and J calls.
• Call classification by population achieved accuracy rates significantly above chance.
• San Pablo and Amazoonico populations showed the greatest vocal divergence, while Hormiga and Zancudococha showed the least.

Conclusions:

• This research provides the first evidence of vocal dialects within a wild neotropical primate subspecies.
• Habitat acoustics, social dynamics, and genetic drift are proposed as potential factors influencing these vocal differences.