Varola Mila, Verga Laura, Sroka Marlene Gunda Ursel, Villanueva Stella, Charrier Isabelle, Ravignani Andrea
Comparative Bioacoustics Research Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.
Research Department, Sealcentre Pieterburen, Pieterburen, the Netherlands.
PeerJ. 2021 Nov 15;9:e12431. doi: 10.7717/peerj.12431. eCollection 2021.
The ability to discriminate between familiar and unfamiliar calls may play a key role in pinnipeds' communication and survival, as in the case of mother-pup interactions. Vocal discrimination abilities have been suggested to be more developed in pinniped species with the highest selective pressure such as the otariids; yet, in some group-living phocids, such as harbor seals (), mothers are also able to recognize their pup's voice. Conspecifics' vocal recognition in pups has never been investigated; however, the repeated interaction occurring between pups within the breeding season suggests that long-term vocal discrimination may occur. Here we explored this hypothesis by presenting three rehabilitated seal pups with playbacks of vocalizations from unfamiliar or familiar pups. It is uncommon for seals to come into rehabilitation for a second time in their lifespan, and this study took advantage of these rare cases. A simple visual inspection of the data plots seemed to show more reactions, and of longer duration, in response to familiar as compared to unfamiliar playbacks in two out of three pups. However, statistical analyses revealed no significant difference between the experimental conditions. We also found no significant asymmetry in orientation (left . right) towards familiar and unfamiliar sounds. While statistics do not support the hypothesis of an established ability to discriminate familiar vocalizations from unfamiliar ones in harbor seal pups, further investigations with a larger sample size are needed to confirm or refute this hypothesis.
辨别熟悉和不熟悉叫声的能力可能在鳍足类动物的交流和生存中发挥关键作用，就像母婴互动的情况一样。有人认为，在选择性压力最大的鳍足类物种（如海狗科动物）中，声音辨别能力更为发达；然而，在一些群居的海豹科动物中，如港海豹（），母亲们也能够识别自己幼崽的声音。幼崽对同种个体声音的识别从未被研究过；然而，繁殖季节幼崽之间反复的互动表明可能会发生长期的声音辨别。在这里，我们通过向三只康复的海豹幼崽播放不熟悉或熟悉幼崽的叫声来探究这一假设。海豹在其一生中第二次进入康复中心的情况并不常见，本研究利用了这些罕见的案例。对数据图的简单目视检查似乎显示，在三只幼崽中的两只中，与不熟悉的叫声回放相比，熟悉的叫声回放引起了更多、持续时间更长的反应。然而，统计分析显示实验条件之间没有显著差异。我们还发现，海豹幼崽对熟悉和不熟悉声音的朝向（左. 右）没有显著的不对称性。虽然统计数据不支持港海豹幼崽具备辨别熟悉叫声和不熟悉叫声的既定能力这一假设，但需要进一步以更大的样本量进行调查来证实或反驳这一假设。
