There’s hardly ever time to jot down about each cool science-y story that comes our manner. So this yr, we’re as soon as once more working a particular Twelve Days of Christmas collection of posts, highlighting one science story that fell by way of the cracks in 2022, every day from December 25 by way of January 5. At this time: Scientists connected video cameras onto dolphins to seize the sights and sounds of the animals as they hunted for prey to be taught extra about their feeding habits.

Scientists connected GoPro cameras to 6 dolphins and captured the sights and sounds of the animals as they hunted and devoured numerous species of fish—even squealing in victory on the seize of child sea snakes, in line with an August paper revealed within the journal PLoS ONE. Whereas sound and video has beforehand been recorded for dolphins discovering and consuming useless fish, per the authors, that is the primary footage combining sound and video from the dolphins’ viewpoint as they pursued stay prey whereas freely swimming. The audio aspect enabled the scientists to be taught extra about how the dolphins communicated whereas looking.

Sam Ridgway and his colleagues on the Nationwide Marine Basis in San Diego, California, have performed earlier analysis on dolphins. They thought they might be taught much more concerning the animals’ looking and feeding methods utilizing cheap industrial GoPro cameras to document sounds in addition to visuals. The excessive frames per second (60, 90, or 120 FPS) enabled them to look at modifications in habits body by body.

The US Navy trains captive dolphins to establish mines, amongst different makes use of. (Though the dolphins are technically free to swim away, most “select” to stay round.) Two of these dolphins—recognized as S and Okay—have been led out by their coach’s boat into San Diego Bay. There they got free rein to forage for meals for 50 minutes. Footage was captured for 15 such outings for dolphin S, and 5 outings for dolphin Okay. Dolphins B and T wore cameras whereas swimming in an above-ground 6×12 meter sea water pool. Reside Pacific mackerel, sardines, and Northern anchovies from a stay bait provider have been let loose within the pool so  B and T might hunt. Lastly, dolphins Y and Z have been filmed by the way capturing prey whereas freely swimming within the open ocean.

Over the course of the research, S caught 69 fish and Okay caught 40 fish, together with noticed sand bass, barred sand bass, smelt, yellowfin croaker, California halibut, and pipefish. The fish have been captured each close to the floor (notably smelt) and, extra steadily, on the ocean flooring, lurking in patches of vegetation. The audio revealed that S, for instance, would buzz and squeal to seek out the hidden fish within the latter state of affairs, gobbling up a mouth filled with the sediment, swallowing the fish and ejecting the sediment and any plant materials again into the water. (One fish did handle to flee the dolphin jaws of loss of life and swim away.)

Among the many shocking findings was the flexibility of all of the dolphins to open their higher and decrease lips to suck prey into their mouths. That is how dolphins B (collected within the Eighties within the Gulf of Mexico) and T captured their fish within the sea water pool, utilizing a facet swipe movement of the top. There have been a couple of examples of so-called “ram feeding”—during which prey is quickly overtaken and clasped within the jaws earlier than being swallowed—particularly when looking close to the floor, however most feeding occasions primarily used the suction technique.

T had been stranded on a Florida seashore as a child in 2013 and raised at Sea World of Florida, so T had by no means been noticed catching stay fish earlier than. However after watching B seize prey, T caught on and started looking with glee. “His captures have been attended by a lot squealing,” the authors wrote.

Dolphins Z and Y have been additionally recorded squealing in victory whereas capturing prey, and Z truly ate up 8 (probably new child) yellow-bellied sea snakes—an uncommon alternative, since dolphins have not beforehand been identified to feed on sea snakes (though they’ve been noticed taking part in “cat and mouse” with sea snakes). “Maybe the dolphin’s lack of expertise in feeding with dolphin teams within the wild led to the consumption of this outlier prey,” the authors wrote. Fortuitously, “Our dolphin displayed no indicators of sickness after consuming the small snakes.”

DOI: PLoS ONE, 2022. 10.1371/journal.pone.0265382  (About DOIs).