This study collected acoustic information on false killer whales (Pseudorca crassidens) in Mexican waters, close to Roca Partida Island, Revillagigedo Archipelago. In total, 321 whistles were collected after we found a group with at least ten individuals. The high prevalence of ascending contour types [upsweep (type I): 42.99%] contradicted the idea that false killer whales mostly produce constant whistles. Lack of well-established reproducibility criteria for whistle type categorization among studies may have generated results different from those expected for signal modulation. Future acoustic and ecological studies should be conducted to help clarify these findings and expand the limited knowledge about this species.

中文翻译：

---

墨西哥伪虎鲸 (Pseudorca crassidens) 的录音（左）

这项研究收集了墨西哥水域中假虎鲸 ( Pseudorca crassidens ) 的声学信息，该海域靠近 Revillagigedo 群岛的 Roca Partida 岛。在我们找到一个至少有 10 个人的团体后，总共收集了 321 条口哨声。上升轮廓类型的高流行率 [upsweep (type I): 42.99%] 与假虎鲸主要产生持续哨声的观点相矛盾。研究中缺乏完善的哨声类型分类的可重复性标准可能会产生与信号调制预期结果不同的结果。应进行未来的声学和生态研究，以帮助澄清这些发现并扩展有关该物种的有限知识。