Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, China.
PeerJ. 2023 Jan 13;11:e14628. doi: 10.7717/peerj.14628. eCollection 2023.
Turtle vocalizations play an important role throughout their lives by expressing individual information (position, emotion, or physiological status), reflecting mating preferences, and synchronizing incubation. The Chinese striped-neck turtle () is one of the most widely distributed freshwater turtles in China, whose wild population is critically endangered. However, its vocalization has not been studied, which can be the basis for behavioral and ecological studies.
Five different sex-age groups of turtles were recorded underwater in a soundproof room. Cluster analysis and principal component analysis for classification of Chinese striped-neck turtle calls were unreasonable. The turtle calls were manually sought using visual and aural inspection of the recordings in Raven Pro 1.5 software and classified according to differences perceived through auditory inspection and the morphological characteristics of the spectrograms. The results of similarity analysis verified the reliability of manual classification. We compared the peak frequency of the calls among different age and sex groups.
We identified ten call types, displayed their spectra and waveforms, and described their auditory characteristics. Most calls produced by the turtles were low-frequency. Some high-frequency call types, that are common in other turtle species were also produced. Similar to other turtles, the Chinese striped-neck turtle generates harmonic vocalizations. Courtship behaviors were observed when one of the call types occurred in the mixed-sex group. Adult females produced more high-frequency call types, and subadult males had higher vocalizations than other groups. These results provide a basis for future research on the function of vocalizations, field monitoring, and conservation of this species.
海龟的发声在其一生中起着重要作用，通过表达个体信息（位置、情绪或生理状态）、反映交配偏好以及同步孵化。中华花龟（）是中国分布最广的淡水龟之一，其野生种群已濒临灭绝。然而，其发声尚未得到研究，这可以作为行为和生态研究的基础。
在隔音室内对五个不同性别年龄组的海龟进行水下录音。聚类分析和主成分分析对中华花龟叫声的分类不合理。在 Raven Pro 1.5 软件中通过视觉和听觉检查对录音进行手动检索，根据听觉检查和频谱图形态特征的差异对海龟叫声进行分类。相似性分析的结果验证了手动分类的可靠性。我们比较了不同年龄和性别组的叫声的峰值频率。
我们确定了十种叫声类型，展示了它们的频谱和波形，并描述了它们的听觉特征。海龟发出的叫声大多为低频。也产生了一些高频叫声类型，这在其他龟种中也很常见。与其他海龟一样，中华花龟会发出谐波叫声。当混合性别组中出现一种叫声类型时，会观察到求偶行为。成年雌龟发出的高频叫声类型更多，亚成体雄龟的叫声比其他组更高。这些结果为未来对发声功能、野外监测和该物种保护的研究提供了依据。
