We rarely have time to write about all the cool science stories that come our way. Posting a special 12 Days of Christmas series. Learn more about feeding behavior by capturing the sights and sounds of animals as they search for prey.
According to an August paper published in the journal PLoS ONE, scientists attached GoPro cameras to six dolphins to capture and hear them hunting and devouring different types of fish. According to the authors, dolphins finding and eating dead fish had previously been recorded by audio and video, but the combination of sound and video from the perspective of dolphins chasing live prey while swimming freely. This is my first video. Speech elements have allowed scientists to learn more about how dolphins communicate while hunting.
Sam Ridgeway and his colleagues at the National Ocean Foundation in San Diego, California, have conducted previous research on dolphins. They figured they could learn more about animal hunting and feeding strategies by recording audio and video using his cheap, off-the-shelf GoPro camera. High frames per second (60, 90, or 120 FPS) allowed us to observe changes in behavior from frame to frame.
The U.S. Navy uses captive dolphins to train them to identify mines and other uses. (Technically dolphins are free to swim away, but most “choose” to stay there.) Her two of these dolphins (identified as S and K) was taken out to San Diego Bay by a trainer’s boat. There they were free to forage for 50 minutes. Footage was taken of 15 outings for Dolphin S and 5 outings for Dolphin K. Live Pacific mackerel, sardines, and otters from a live bait supplier were released into the pool so that B and T could hunt. Finally, dolphins Y and Z were filmed catching prey by chance while swimming freely in the open ocean.
During the course of the survey, S caught 69 fish and K caught 40 fish. These fish include spotted sand bass, bird sand bass, smelt, yellowfin perch, California halibut and pipefish. Fish were caught both near the surface (particularly smelt) and more often on the seabed, lurking in patches of vegetation. , swallowing a mouthful of sediment, swallowing fish, and expelling sediment and plant material into the water. was.)
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Dolphin S with camera mounted on the left side of the harness.
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The Dolphin S burrows into the seafloor to catch fish. Note that the white of the eye or sclera (arrow) rotates the eye toward the fish. C. Dolphin S attracts fish, and the lip widens behind the cleft region, indicating an enlarged upper dentition and laryngeal region.
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Dolphin T (a) shows fish position, right eye rotated forward. (b) When captured, the lower lip is pulled down to reveal gums, teeth and fish (arrows) in the mouth. (c) While turning the fish, the dolphin pulls down the lip to enlarge the laryngeal region, apparently causing a decrease in intraoral pressure, but the fish mostly escapes.
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Fish catching sequence. A. A view of the dolphin’s predecessor while catching fish. B. Relative amplitudes of sounds recorded when Dolphin S. spotted, tracked, and captured wild fish. C. Audible sound spectrogram showing changes in call pulse rate and peak frequency characteristics.
Among the surprising discoveries was the ability of all dolphins to open their upper and lower lips to suck prey into their mouths. A method of catching fish in a saltwater pool using motion. There have been several instances of so-called “ram feeding”, especially when hunting near the surface.
T was stranded on a beach in Florida as a baby in 2013 and was raised at Sea World of Florida, so I never witnessed T catching live fish. But after seeing B catch prey, T caught up to it and happily began hunting.
Dolphins Z and Y were also documented giving a triumphant shriek while catching prey, and Z actually fed on eight (presumably newborn) yellow-bellied sea snakes. They have been observed playing “cat and mouse” with sea snakes). “Perhaps dolphins’ inexperience in feeding wild pods of dolphins led them to consume this unusual prey,” the authors wrote. Fortunately, “our dolphins showed no signs of illness after eating the tiny snake.”
DOI: PLoS ONE, 2022. 10.1371/journal.pone.0265382 (About DOI).
Dolphin Z catching sea snakes in the Pacific with head jerk and victory call. Credit: Ridgeway et al., 2022
