# First description of 'vocal sparring': a socio-acoustic behaviour in juvenile male sperm whales (Physeter macrocephalus) off Mauritius

L Berkenbaum, H Glotin, F Sarano, O Adam, R Heuzey, A Preud'Homme

► To cite this version:

L Berkenbaum, H Glotin, F Sarano, O Adam, R Heuzey, et al. First description of 'vocal sparring': a socio-acoustic behaviour in juvenile male sperm whales (Physeter macrocephalus) off Mauritius. International Bioacoustics Congress, Sep 2025, Kerteminde, Denmark. 2025. [https://hal-05267460v1](https://hal-05267460v1)

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https://univ-tln.hal.science/hal-05267460v1

Submitted on 18 Sep 2025

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d'Alembert
Institut Jean le Rond d'Alembert

UNIVERSITÉ DE
TOULON

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biodiversa+
European Biodiversity Partnership

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Indian Ocean
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IBAC 2025
KERTEMINDE | DENMARK

© René Heuzey
Un Océan De Vie
Label Bleu Production

# First description of ‘vocal sparring’: a socio-acoustic behaviour in juvenile male sperm whales (*Physeter macrocephalus*) off Mauritius

L. Berkenbaum a,b,f, H. Glotin a,b,f, F. Sarano b,f, O. Adam c,d,f, R. Heuzey b,e,f and A. Preud'homme b,e,f.

a) Toulon Univ., Aix Marseille Univ, CNRS, LIS, D'INI team, Marseille, France b) Longitude 181, Valence, France c) Sorbonne Univ., CNRS, Inst. d'Alembert, Paris, France, d) Univ. Paris-Saclay, CNRS, Inst. of Neurosciences, Gif/Yvette, France e) Indian Ocean Marine Life Foundation, Mauritius f) CIAN, Center for AI in Natural Acoustics, Toulon, France.

lara.berkenbaum@lis-lab.fr, glotin@univ-tln.fr, saranofrancois@gmail.com, olivier.adam@sorbonne-universite.fr ; https://cian.univ-tln.fr, https://www.longitude181.org/

## Introduction

**Context:** Juvenile males Pm in matrilineal units → key period for social/vocal development.
**Gap:** Social & vocal interactions poorly documented.
**Aim:** Define & describe a new socio-acoustic behaviour.

Mauritius Island

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## Study context & Methods

**Program:** 'La Voix Des Cachalots' [1,2]
**Sampling effort:** 10 yrs, passive obs, non-invasive.
**Subjects:** 2 dyads, distinct social units.
**Analysis:** ID [3], behavioural annot, vocal description.

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## Results

**Definition**
**vocal sparring**
voluntary, repeated interactions between same-age juvenile males, combining close physical contact and sustained clicks trains, without aggression.

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<figure><img src="image_16.png" /><figcaption>**Figure 1.** Example of vocal sparring Eliot & TB (2019, video 4'31). Dyadic interaction with a series of sustained clicks (①② simple and ③④ simple sequence).</figcaption></figure>

* Prolonged dyadic exchanges between same-age juvenile males;

* Close physical contacts: mouth-to-mouth, mouth-to-body, head-to-head, body-to-body, rolls, repeated approaches/retreats, mouth open/closed[4];

* Specific postures: head down or up, vertical face-to-face;

* Vocalisations: clicks trains, often overlapping, interspersed with silences, occasionally followed by fast trains ('buzzes').

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<figure><img src="image_18.png" /><figcaption>**Figure 2.** Example of vocal sparring Ali & Daren (2023, video 2'44). Dyadic interaction with a series of sustained clicks (①② simple and ③④ overlapping sequence).</figcaption></figure>

## Discussion

### NOT OBSERVED

♀ pairs | ♂ pairs | ♂ (≠ ages) | Adult-juvenile pairs

### OBSERVED

♂ pairs (same age) → vocal sparring

Dyadic, prolonged, repeated → fits criteria of social play (non-aggression, spontaneous, voluntary[5,6]).

No coda but prolonged, overlapping clicks trains → specific acoustic form of play.

Unprecedented sounds → new window into vocal development & social learning in young males.

## Hypothesis

* Reinforces social bonds among juvenile males.

* Fosters social & communicative skills.

* Recurrence across years/dyads → **stable** social behaviour.

* Provide new insights into juvenile socialisation & evolution of vocal play.

## Perspectives

* Ethogram: standardise sequences descriptions.

* Quantitative analyses: behaviour & vocal patterns.

* Longitudinal study: track development of juvenile males over years.

* Sound-behaviour link: assign clicks to individuals[7].

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Video clicks assignment [7]

## Acknowledgments

We thank Longitude 181, Un Océan de Vie and Label Bleu productions for fieldwork, video recordings and data support. Thanks to N. Boodhonee and A. Preud'homme for their valuable participation in the fieldwork. This study was conducted under the official authorization of the Mauritius Authority. The project "La Voix Des Cachalots" benefited from the support of the Mauritian Prime Minister's Office, MCSEA (Dr. Réza Badal & team), AFRC (Mr. Satish Kadhun), MFDC (Mr. Sachin Jootun & Miss Eliana Timol), and the Tourism Authority (Miss Khoudijah Boodoo). We are grateful to SMIoT, V. Gies and V. Barchasz for their help with OPALE recorder. This research was supported by Biodiversa+ (EUROPAM project), CIAN, LIS UTLN and Indian Ocean Marine Life Foundation. We also warmly thank Walter M.X. Zimmer and Daniela Silvia Pace for their support as CSI members.

## References

[1] Sarano et al., 2021. Kin Relationships in cultural species of the marine realm: case study of a social group of sperm whales off Mauritius.

[2] 'La Voix des Cachalot's, Longitude181 research programme, https://www.longitude181.org & https://www.cian.univ-tln.fr.

[3] Sarano, V. et al., 2022. Underwater photo-identification of sperm whales off Mauritius. Marine Biology Research.

[4] Berkenbaum, L., 2021. Étude étho-acoustique d'un groupe social de cachalots résident de l'île Maurice (océan indien).

[5] Bekoff, M., 1972. The development of social interaction, play, and metacommunication in mammals: an ethological perspective.

[6] Burghardt, G., 2014. A Brief Glimpse at the Long Evolutionary History of Play. Animal Behavior and Cognition 2(90).

[7] Berkenbaum, L. et al., 2025. Analysis of sperm whale (*Physeter macrocephalus*) dialogues, click by click: an ethoacoustic approach.