# Vocalizations Reveal Species Differences in Endangered Lion Tamarins (Primates, Callitrichidae)

## TL;DR

This study shows that lion tamarin species can be distinguished by their vocalizations, with frequency-based acoustic features being most useful for identification.

## Contribution

The first comparative analysis of seven vocalization types across all four lion tamarin species using acoustic parameters.

## Key findings

- Spectral parameters like peak frequency and frequency at 5% and 95% best distinguish lion tamarin species.
- Leontopithecus caissara is the most acoustically distinct species among the four.
- Trills showed the most interspecific variation in acoustic features.

## Abstract

Acoustic communication is important for social cohesion and territory defense in forest primates, including the endangered lion tamarins (genus Leontopithecus). Although vocalizations of individual species have been studied, there is still no comparative analysis examining whether acoustic parameters can reliably distinguish among all four species. We hypothesized that species‐specific differences in acoustic features allow discrimination among lion tamarin species, and we predicted that both spectral and temporal parameters would reveal interspecific variation. To test this, we analyzed seven shared vocalizations (long calls, whines, trills, rasps, clucks, tsicks, and peeps) from the black‐faced lion tamarin (Leontopithecus caissara), golden lion tamarin (Leontopithecus rosalia), golden‐headed lion tamarin (Leontopithecus chrysomelas), and black lion tamarin (Leontopithecus chrysopygus). Acoustic data were obtained from online sound libraries and analyzed using Raven Pro software. Spectral and temporal parameters, including frequency at 5% and 95%, peak frequency, center frequency, and bandwidth 90% were measured, followed by principal component analysis (PCA) and nonparametric statistical tests to identify species‐specific differences. Our results revealed significant interspecific differences across multiple vocalizations, with spectral parameters being the most relevant for distinguishing species, whereas temporal parameters contributed less. L. caissara emerged as the most acoustically distinct species, while L. rosalia and L. chrysopygus exhibited the greatest vocal similarity. In conclusion, this study provides the first comparative analysis of seven vocalization types across all four lion tamarin species, establishing an acoustic baseline, confirming the importance of spectral parameters for species differentiation, and demonstrating the potential of vocalizations for conservation applications.

Spectral parameters of vocalizations distinguish lion tamarin species. Peak frequency, center frequency, and frequency at 5% and 95% were the most informative measures for separating species, with the trill being the vocalization that showed the most differences, and Leontopithecus caissara being the most distinct species of all.

Call types and comparison: The study analyzes and compares seven shared vocalizations across four lion tamarin species (Leontopithecus rosalia, Leontopithecus chrysomelas, Leontopithecus chrysopygus, and Leontopithecus caissara), testing the hypothesis that species‐specific acoustic parameters allow discrimination among species.Species‐specific differences: Significant interspecific differences were detected, driven mainly by frequency at 5% and 95%, peak frequency, and center frequency, supporting the prediction that these parameters distinguish species.Conservation implications: Our results provide an acoustic baseline for all four lion tamarin species across seven different vocalizations and demonstrate the potential of acoustic parameters for conservation.

Call types and comparison: The study analyzes and compares seven shared vocalizations across four lion tamarin species (Leontopithecus rosalia, Leontopithecus chrysomelas, Leontopithecus chrysopygus, and Leontopithecus caissara), testing the hypothesis that species‐specific acoustic parameters allow discrimination among species.

Species‐specific differences: Significant interspecific differences were detected, driven mainly by frequency at 5% and 95%, peak frequency, and center frequency, supporting the prediction that these parameters distinguish species.

Conservation implications: Our results provide an acoustic baseline for all four lion tamarin species across seven different vocalizations and demonstrate the potential of acoustic parameters for conservation.