During ram feeding, prey is rapidly overtaken and clasped in jaws on the way to being swallowed. This negative intraoral pressure facilitates capturing, ingesting and manipulating prey in the mouth. For most odontocetes studied, observers have shown that suction for feeding is produced by hyolingual retraction and depression that withdraws the tongue and expands the throat to create a negative (sub-ambient) intraoral pressure. The first feeding concept involves strong intraoral suction which is used by most fish and marine mammals. There are two main concepts on odontocete (toothed whales) feeding techniques. We also wanted to see dolphin’s eye, throat and mouth movements during prey capture. Specifically we wanted to listen to dolphin sounds while they chase, capture and eat prey. Video taken simultaneously by the same camera allowed us to begin relating dolphin sounds with behavior. Audio recordings from the camera allowed us to hear human audible sounds produced by the dolphins as they swam, searched, pursued, and captured prey.

Two other Navy dolphins were observed capturing live fish in a sea water pool while two additional Navy dolphins were observed feeding opportunistically during open water sessions in the Pacific Ocean (During this open water mine simulator training the acoustics and behavior specific to that task were described by Ridgway et al, but not the incidental fish captures noted here). For the first time, two Navy dolphins wearing these cameras hunted and captured live fish while freely swimming in San Diego Bay.

Our hypothesis was that we could make useful observations of dolphin’s fish captures employing inexpensive commercially available cameras that recorded video and audio. However, sound and video together have never been used to observe behavior of dolphins and of the live fish they capture and consume. Sounds and video have also been recorded from dolphins finding and consuming dead fish. Sounds and head jerks of toothed whales in the wild and in the laboratory setting have been recorded as they captured live prey. Monk seals equipped with special cameras have been observed capturing fish. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.Ĭameras have been attached to various marine mammals for observations of behavior under water. In addition, authors received funding from the National Marine Mammal Foundation (). This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the manuscript and its Supporting Information Files.įunding: The authors (SR, DD) received funding from the Office of Naval Research ( ).

Received: FebruAccepted: JPublished: August 17, 2022Ĭopyright: © 2022 Ridgway et al. PLoS ONE 17(8):Įditor: Songhai Li, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, CHINA Fish continued escape swimming even as they entered the dolphins’ mouth, yet the dolphin appeared to suck the fish right down.Ĭitation: Ridgway S, Dibble DS, Baird M (2022) Sights and sounds dolphins, Tursiops truncatus preying on native fish of San Diego Bay and offshore in the Pacific Ocean. During captures, the dolphins’ lips flared to reveal nearly all of the teeth. If fish escaped, the dolphin continued the chase and sonar clicks were heard less often than the continuous terminal buzz and squeal. Squeals continued as the dolphin seized, manipulated and swallowed the prey. Squeals were bursts of clicks that varied in duration, peak frequency, and amplitude. On approaching prey, click intervals shorten into a terminal buzz and then a squeal. Searching dolphins clicked at intervals of 20 to 50 ms. Notably, one of these dolphins was observed to consume 8 yellow-bellied sea snakes ( Hydrophis platurus). Two additional dolphins were observed feeding opportunistically during open water sessions in the Pacific Ocean. Two other dolphins were observed capturing 135 live native fish in a sea water pool. 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. For the first time, dolphins wearing video cameras were observed capturing and eating live native fish.

Navy dolphins 3d