Vocal ontogeny in neotropical singing mice (Scotinomys)

Area of Science:

• Animal behavior
• Bioacoustics
• Evolutionary biology

Background:

• Vocalizations in young animals are crucial for communication but change significantly with sexual maturity.
• The developmental link between juvenile and adult acoustic communication is under-researched.
• Singing mice (Scinomys) exhibit complex adult songs, but their juvenile vocal behavior is undescribed.

Purpose of the Study:

• To analyze the vocal development of Neotropical singing mice (Scinomys teguina and S. xerampelinus) from birth to sexual maturity.
• To investigate the ontogenetic relationship between juvenile isolation calls and adult advertisement songs.
• To identify species-specific vocal differences during development.

Main Methods:

• Daily vocal recordings of singing mouse pups from birth to weaning, and continued until sexual maturity.
• Comparative analysis of vocalizations in two sister species, S. teguina and S. xerampelinus.
• Examination of note composition, structure, and temporal organization in juvenile and adult vocalizations.

Main Results:

• Singing mouse pups were vocal early in life, ceasing vocalizations before weaning.
• A silent period preceded the onset of adult advertisement song production at sexual maturity.
• While basic song notes were present from birth, their organization differed significantly between pups and adults.
• Adult song structure appeared de novo, not gradually developing from juvenile calls.

Conclusions:

• The fundamental elements of adult songs are available early in development.
• Shifts in acoustic signal structure and prevalence are driven by distinct selection pressures across life stages (dependency, dispersal, territoriality).
• This study illuminates how conserved acoustic signaling provides foundational elements for species-specific adult vocalizations.