Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)

The effects of hormonal contraception in non-human primates have been studied predominantly in relation to reproductive physiology. To date, no study has investigated how hormonal contraception affects vocal patterns in non-human primates. As part of our long-term research into the vocal behavior of...

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Main Authors: Michal Hradec, Petra Bolechová, Hana Vostrá-Vydrová
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Veterinary Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fvets.2025.1574926/full
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author Michal Hradec
Petra Bolechová
Hana Vostrá-Vydrová
author_facet Michal Hradec
Petra Bolechová
Hana Vostrá-Vydrová
author_sort Michal Hradec
collection DOAJ
description The effects of hormonal contraception in non-human primates have been studied predominantly in relation to reproductive physiology. To date, no study has investigated how hormonal contraception affects vocal patterns in non-human primates. As part of our long-term research into the vocal behavior of southern yellow-cheeked gibbons (Nomascus gabriellae) in zoos, we have managed to obtain vocal datasets from four adult contracepted (Nexplanon® and Depo-Provera®) females of this species. In addition, we also recorded coda vocalizations (i.e., male calls added after the completion of the great call) from three paired males who are partners of three of the four females studied. We quantified 11 acoustic features in the female great calls and five acoustic features in the male coda vocalizations, for which we applied a Principal Component Analysis (PCA) and subsequently components were tested using multivariate Generalized Linear Mixed Models (GLMM). Our study revealed that hormonal contraception did indeed affect the vocal structure of great call in southern yellow-cheeked gibbon females. In contrast, our study did not reveal any flexible adjustment of the structure of the coda vocalization in direct response to changes in the females’ song. In female great call, we found that the Group 1 call component and Group 2 call component were not affected by the hormonal contraceptive (Depo-Provera®) in the during-application period. However, it was noteworthy that once the effects of contraception had worn off (post-application period), the values of components did not return to pre-application periods but continued to change. Conversely, although the values of the Group 1 call component and Group 2 call component were most greatly affected by the contraceptive Nexplanon® (during-application period). The values of both components tended to return to pre-treatment levels once the effects had waned. There was a change in the values of the Group 3 call component only after application of the contraceptive Nexplanon®. These values remained significantly higher than the values at the pre-application level once the effects waned. This study provides the first evidence of changes in the stable vocal patterns of female southern yellow-cheeked gibbons as a consequence of the application of hormonal contraception.
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publisher Frontiers Media S.A.
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spelling doaj-art-e58f736b72984b37b08e78995966a8322025-08-20T02:09:02ZengFrontiers Media S.A.Frontiers in Veterinary Science2297-17692025-04-011210.3389/fvets.2025.15749261574926Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)Michal HradecPetra BolechováHana Vostrá-VydrováThe effects of hormonal contraception in non-human primates have been studied predominantly in relation to reproductive physiology. To date, no study has investigated how hormonal contraception affects vocal patterns in non-human primates. As part of our long-term research into the vocal behavior of southern yellow-cheeked gibbons (Nomascus gabriellae) in zoos, we have managed to obtain vocal datasets from four adult contracepted (Nexplanon® and Depo-Provera®) females of this species. In addition, we also recorded coda vocalizations (i.e., male calls added after the completion of the great call) from three paired males who are partners of three of the four females studied. We quantified 11 acoustic features in the female great calls and five acoustic features in the male coda vocalizations, for which we applied a Principal Component Analysis (PCA) and subsequently components were tested using multivariate Generalized Linear Mixed Models (GLMM). Our study revealed that hormonal contraception did indeed affect the vocal structure of great call in southern yellow-cheeked gibbon females. In contrast, our study did not reveal any flexible adjustment of the structure of the coda vocalization in direct response to changes in the females’ song. In female great call, we found that the Group 1 call component and Group 2 call component were not affected by the hormonal contraceptive (Depo-Provera®) in the during-application period. However, it was noteworthy that once the effects of contraception had worn off (post-application period), the values of components did not return to pre-application periods but continued to change. Conversely, although the values of the Group 1 call component and Group 2 call component were most greatly affected by the contraceptive Nexplanon® (during-application period). The values of both components tended to return to pre-treatment levels once the effects had waned. There was a change in the values of the Group 3 call component only after application of the contraceptive Nexplanon®. These values remained significantly higher than the values at the pre-application level once the effects waned. This study provides the first evidence of changes in the stable vocal patterns of female southern yellow-cheeked gibbons as a consequence of the application of hormonal contraception.https://www.frontiersin.org/articles/10.3389/fvets.2025.1574926/fullgibbonbreeding programsvocalizationzooNomascus
spellingShingle Michal Hradec
Petra Bolechová
Hana Vostrá-Vydrová
Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)
Frontiers in Veterinary Science
gibbon
breeding programs
vocalization
zoo
Nomascus
title Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)
title_full Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)
title_fullStr Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)
title_full_unstemmed Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)
title_short Effects of hormonal contraception on vocal patterns of captive southern yellow-cheeked gibbons (Nomascus gabriellae)
title_sort effects of hormonal contraception on vocal patterns of captive southern yellow cheeked gibbons nomascus gabriellae
topic gibbon
breeding programs
vocalization
zoo
Nomascus
url https://www.frontiersin.org/articles/10.3389/fvets.2025.1574926/full
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AT hanavostravydrova effectsofhormonalcontraceptiononvocalpatternsofcaptivesouthernyellowcheekedgibbonsnomascusgabriellae