Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands
Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands.
J Exp Biol. 2020 May 27;223(Pt 10):jeb207878. doi: 10.1242/jeb.207878.
Group-living animals must communicate to stay in contact. In long-finned pilot whales, there is a trade-off between the benefits of foraging individually at depth and the formation of tight social groups at the surface. Using theoretical modelling and empirical data of tagged pairs within a group, we examined the potential of pilot whale social calls to reach dispersed group members during foraging periods. Both theoretical predictions and empirical data of tag pairs showed a potential for communication between diving and non-diving group members over separation distances up to 385 m (empirical) and 1800 m (theoretical). These distances match or exceed pilot whale dive depths recorded across populations. Call characteristics and environmental characteristics were analysed to investigate determinants of call detectability. Longer calls with a higher sound pressure level (SPL) that were received in a quieter environment were more often detected than their shorter, lower SPL counterparts within a noisier environment. In a noisier environment, calls were louder and had a lower peak frequency, indicating mechanisms for coping with varying conditions. However, the vulnerability of pilot whales to anthropogenic noise is still of concern as the ability to cope with increasing background noise may be limited. Our study shows that combining propagation modelling and actual tag recordings provides new insights into the communicative potential for social calls in orientation and reunion with group members for deep-diving pilot whales.
群居动物必须通过交流来保持联系。在长鳍领航鲸中，个体在深处觅食和在水面形成紧密的社会群体之间存在着权衡。利用理论模型和群体内标记对的经验数据，我们研究了领航鲸社会叫声在觅食期间到达分散的群体成员的潜力。理论预测和标记对的经验数据都表明，潜水和非潜水的群体成员之间存在潜在的沟通能力，分离距离可达 385 米（经验）和 1800 米（理论）。这些距离与跨种群记录的领航鲸潜水深度相匹配或超过。分析了叫声特征和环境特征，以研究叫声可检测性的决定因素。在嘈杂的环境中，具有更高声压级 (SPL) 的较长叫声比在安静环境中具有较短 SPL 的叫声更容易被检测到。在嘈杂的环境中，叫声更大，峰值频率更低，这表明存在应对不同条件的机制。然而，由于应对不断增加的背景噪音的能力可能有限，领航鲸对人为噪音的脆弱性仍然令人担忧。我们的研究表明，将传播建模和实际标记记录相结合，为深潜领航鲸在定向和与群体成员团聚方面的社交叫声的交流潜力提供了新的见解。
