Sound production in sea turtle nests and hatchlings (<i>Eretmochelys imbricata</i> and <i>Caretta caretta</i>) in Northeast Brazil

Sea turtles have been considered the least vocal of living reptiles, but recent studies are changing this perception. Here, we aimed to investigate the acoustics of hatchlings of, <i>Eretmochelys imbricata</i> and <i>Caretta caretta</i> in Northeast Brazil, to describe their acoustic signals and compare sound structure within and between species. We monitored 13 km in Ipojuca, southern coast of Pernambuco State. We recorded five nests of each species and the hatchlings’ walk to the sea in 2020/2021. We recorded 12 sonotypes in <i>C. caretta</i> and 5 in <i>E. imbricata</i>, increasing the number of described signals. Nevertheless, not all sonotypes were produced by all or in the different developmental stages. Some of the sounds for both species reached ultrasonic frequencies. The sound structure varied between <i>C. caretta</i> nests, suggesting a potential vocal signature, but the sound structure had no variation between <i>E. imbricata</i> nests. The sound structure varied between species. Despite their reputation for being silent, this study shows a diverse acoustic repertoire in the target species, further supporting speculations of acoustic signals mediating the potential synchronisation of hatchlings’ departure to the sea. Our signal descriptions could be used for future passive acoustic monitoring of the target species. Future studies should focus on understanding the functionality of acoustic signals in the different life stages.海龟曾被认为是现存爬行动物中鸣声最少的类群，但近期的研究正在改变这一认知。本研究旨在调查巴西东北部的蠵龟（Caretta caretta）和玳瑁（Eretmochelys imbricata）幼崽的声学特性，描述其声学信号，并比较种内及种间的声音结构。研究团队于2020至2021年间，在伯南布哥州南部海岸的伊波茹卡（Ipojuca）开展了13公里的监测工作，对两个物种各5个巢穴以及幼崽入海行进过程进行了录音。本研究在蠵龟中记录到12种声型，在玳瑁中记录到5种声型，扩充了已报道的信号种类数量。不过，并非所有声型都会被所有个体或是在不同发育阶段产生。两个物种的部分鸣声可达超声频段。蠵龟不同巢穴间的声音结构存在差异，提示其存在潜在的鸣声个体识别信号；但玳瑁不同巢穴间的声音结构并无显著差异。不同物种间的声音结构则存在差异。尽管这两类物种素来被认为沉默寡言，但本研究揭示了目标物种拥有丰富多样的鸣声库，进一步支持了"声学信号可介导幼崽同步入海"的推测。本研究对信号的描述可为后续对目标物种开展被动声学监测提供参考。未来的研究可聚焦于阐明不同生命阶段中声学信号的功能。

搜集汇总

背景与挑战

背景概述

该数据集记录了巴西东北部玳瑁和红海龟巢穴及幼龟的声音产生研究，通过监测13公里海岸线并记录巢穴声音，描述了红海龟12种声型和玳瑁5种声型，部分声音达到超声波频率。研究发现红海龟巢穴间声音结构存在差异，可能具有声音签名功能，而玳瑁巢穴间无差异，物种间声音结构也不同，这挑战了海龟沉默的传统认知，并支持声音可能调节幼龟同步入海的假设。