Clicking sounds and cheers of victory form the soundtrack in the first footage recorded from the perspective of dolphins hunting freely off the coast of North America.
The U.S. Navy has strapped on cameras for a scientific study to be published in 2022. trained dolphin To identify undersea mines and protect parts of America nuclear stockpileHe then let them hunt freely in San Diego Bay.
This clever marine mammal did not disappoint. They offered exciting chases and, to the surprise of researchers, even targeted venomous sea snakes.
Despite being such a popular and well-known animal, there are still many fundamental things we don’t know about these highly social and frequently behaved animals. gross Cetaceans, just like how they normally feed.
At least two techniques are widely known to researchers. One is to slurp your prey like noodles from a bowl, and the other is to ram you like a hot dog between rides at the state fair.
But this footage reveals much more.
Camera strapped to six bottlenose dolphins (Tursiops truncatus) Six months of video and audio recordings from the National Marine Mammal Foundation (NMMF) have provided a new level of insight into the hunting strategies and communication of these mammals.
Recording devices were placed on their backs or sides, eerily showing the strange angles of their eyes and mouths.
Although these dolphins are not wild, they are regularly provided hunting opportunities in the open ocean to supplement their regular diet of frozen fish. Therefore, these animals are likely using methods similar to their wild cousins, as NMMF marine mammal veterinarian Sam Ridgway and colleagues explained in 2022.
“While hunting, the dolphins made almost constant clicking sounds at intervals of 20 to 50 milliseconds,” they said. report In their paper.
“As you get closer to the prey, the clicks get shorter, then end with a buzzing sound, then a squealing sound. When you make contact with the fish, the buzzing and squealing sounds are almost constant until the fish is swallowed.” It was.”
frame border=”0″ permission=”accelerometer; autoplay; clipboard write; encrypted media; gyroscope; picture-in-picture. web-share” Referrerpolicy=”strict-origin-when-cross-origin” allowedfullscreen>
Equipped with cameras, the dolphins caught more than 200 fish, including bass, croaker, halibut, smelt, and pipefish. Smelt would often desperately throw themselves into the air in an attempt to escape sophisticated predators.
However, the dolphins swam upside down to track the dolphin’s every movement and give the spinning eyes a clear view. This is a technique previously observed in wild dolphins.
“These dolphins appeared to use both sight and hearing to find prey,” Ridgway and colleagues said. explained. “At long distances, dolphins consistently used echolocation to find fish; up close, vision and echolocation seemed to be used together.”
The cameras also recorded the sounds of the dolphins’ heartbeats as they pumped hard to keep up with the intense activity, and the dolphins still struggled, using suction rather than ramming their prey. It was also revealed that the animal’s surprisingly powerful throat helped it swallow its prey. muscle.
The dolphin primarily sucked in the fish through the side of its open mouth, its throat muscles expanding and its tongue retracted out of the way. Expanding the space in your mouth helps your sucking muscles create negative pressure.
Dolphins have previously been captured playing with snakes, including a river dolphin playing with an eerily large anaconda, but this footage shows for the first time that dolphins may also eat these reptiles. Confirmed.
One dolphin preyed on eight highly venomous yellow water snakes (Platurus hydrophys).
“Our dolphins showed no signs of illness after eating small snakes,” the researchers said. explainedHowever, they acknowledged that since dolphins are captive animals, this could also be abnormal behavior.
“Perhaps this dolphin had no experience feeding with wild dolphin pods, leading to this unusual prey intake.”
The study’s lead author, Sam Ridgway, died at the age of 86 shortly before the study was published, leaving behind a rich research legacy.
“His creative approach to working with Navy dolphins to better understand the species’ behavior, anatomy, health, sonar, and communication will inspire generations of future scientists,” said NMMF animal behaviorist Brittany Jones. It will continue to educate and inspire for many years to come.” said guardian.
Naval-trained dolphins “work in the open sea almost every day,” the NMMF said. explained on the website.
“They can swim away if they want to, and a few have done so over the years, but almost all of them stay.”
This research Pro Swan.
A previous version of this article was published in August 2022.
