National Marine Mammal Foundation, San Diego, CA, United States of America.
Department of Pathology, School of Medicine University of California, San Diego, CA, United States of America.
PLoS One. 2022 Aug 17;17(8):e0265382. doi: 10.1371/journal.pone.0265382. eCollection 2022.
For the first time, dolphins wearing video cameras were observed capturing and eating live native fish. While freely swimming in San Diego Bay, one dolphin caught 69 resident fish, 64 demersal, 5 near surface, while the other caught 40, 36 demersal and 4 near the surface. Two other dolphins were observed capturing 135 live native fish in a sea water pool. Two additional dolphins were observed feeding opportunistically during open water sessions in the Pacific Ocean. Notably, one of these dolphins was observed to consume 8 yellow-bellied sea snakes (Hydrophis platurus). Searching dolphins clicked at intervals of 20 to 50 ms. On approaching prey, click intervals shorten into a terminal buzz and then a squeal. Squeals were bursts of clicks that varied in duration, peak frequency, and amplitude. Squeals continued as the dolphin seized, manipulated and swallowed the prey. If fish escaped, the dolphin continued the chase and sonar clicks were heard less often than the continuous terminal buzz and squeal. During captures, the dolphins' lips flared to reveal nearly all of the teeth. The throat expanded outward. Fish continued escape swimming even as they entered the dolphins' mouth, yet the dolphin appeared to suck the fish right down.
首次观察到戴视频摄像机的海豚捕捉并食用活的本地鱼类。在圣地亚哥湾自由游泳时，一只海豚捕获了 69 条本地鱼，其中 64 条为底栖鱼，5 条在水面附近，另一只海豚捕获了 40 条，36 条为底栖鱼，4 条在水面附近。还观察到另外两只海豚在海水池中捕捉了 135 条活的本地鱼。还观察到另外两只海豚在太平洋的开阔水域中伺机觅食。值得注意的是，其中一只海豚被观察到吞食了 8 条黄腹海蛇（Hydrophis platurus）。觅食的海豚以 20 到 50 毫秒的间隔发出咔哒声。在接近猎物时，咔哒声的间隔会缩短成终端嗡嗡声，然后是尖叫声。尖叫声是一系列咔哒声，持续时间、峰值频率和幅度不同。当海豚抓住、操纵和吞下猎物时，尖叫声会持续不断。如果鱼逃脱了，海豚会继续追逐，并且很少听到声纳咔哒声，而不是连续的终端嗡嗡声和尖叫声。在捕捉过程中，海豚的嘴唇张开，露出几乎所有的牙齿。喉咙向外扩张。即使鱼已经进入海豚的口中，它们仍继续逃脱游泳，但海豚似乎将鱼直接吸入了口中。
