Dolphins with GoPro cameras on them captured amazing images of their hunting habits.
The videos surprised scientists as dolphins used suction to feed and eat venomous sea snakes.
Watch the dolphins point of view and hear their sonar clicks and shouts of victory as they hunt.
Video footage from GoPro cameras tethered to a pair of Navy-trained dolphins reveals the ocean animals’ hunting habits up close for the first time.
Scientists from the National Marine Mammal Foundation fixed the dolphins with their cameras and released them into San Diego Bay. They captured hours of video and sounds that reveal some secrets of dolphin life.
It turns out that the animals use suction to feed, swallow venomous sea snakes, and squeal in victory after a successful hunt.
A video, below, shows the dolphin’s face as it tracks a fish, catches it and swims a victory lap. It’s not just the footage that’s amazing. The shrill, echoing cries of the dolphin are equally revealing. The dolphins emitted sonar clicks as they searched for prey. As they approached a fish, the clicks accelerated to become a hum, punctuated by a squeal as they caught and swallowed their meal.
The research was led by Sam Ridgway, a prominent marine mammal scientist who earned nicknames such as “Doctor Dolphin” and “the father of marine mammal medicine” before he died at his home in San Diego in July.
Ridgway helped found the US Navy Marine Mammal Program more than 60 years ago. This is the program that trained the dolphins in this study. He also founded and led the National Marine Mammal Foundation, the non-profit organization behind the new newspaper. He has devoted his entire career to understanding the behavior, physiology and health of ocean mammals – especially bottlenose dolphins.
These videos are one of your final research efforts. For the first time, Ridgway and his team captured video and sounds of dolphins hunting and eating live fish. An article about the footage was published in PLOS ONE on Wednesday.
“Dr. Ridgway was very proud of these findings and ecstatic to learn that this culmination would be published in PLOS ONE,” Brittany Jones, a scientist at the National Marine Mammal Foundation who worked with the study authors as they completed their paper. , told Insider in an email.
“He was always eager and excited to review the video and audio of these fish catching sessions and recently spoke of his appreciation and admiration for [co-authors] Dianna Samuelson Dibble, Mark Baird, the amazing animals and the animal care team that made this research possible,” said Jones.
A dolphin’s diet included venomous sea snakes
Shockingly for the researchers, a dolphin ate eight venomous sea snakes – a behavior never seen before in dolphins.
The video below shows one of these sea snake meals. After catching the snake, the dolphin shakes its head and emits a high-pitched “victory squeal”.
Did you take this? Was fast.
This is a yellow-bellied sea snake, and it is highly venomous. Scientists assumed that’s why they only observed dolphins playing with snakes and releasing them, not consuming them – especially not consuming eight of them.
Ridgway and his co-authors couldn’t believe their eyes at first. They looked for other fish that might look like a sea snake on camera, but found no other explanation.
“I have read that other large vertebrates rarely attack the yellow-bellied sea snake. There are reports of leopard seals eating and then regurgitating. This snake has the potential to cause neurotoxicity upon ingestion and its venom is considered quite dangerous.” Dr. Barb Linnehan, director of medicine at the National Marine Mammal Foundation, said in an emailed statement to Insider.
The dolphin showed no signs of illness after its meals with sea snakes, the researchers reported.
“Perhaps because the snakes ingested were considered juveniles, they had a lower amount of venom present,” Linnehan said.
Dolphins appear to be sucking feeders
The footage of the sea snake is also revealing because the dolphin caught its prey in the open sea, indicating that it used suction to capture and swallow its food. Previously, researchers assumed that bottlenose dolphins use a technique called sheep feeding, in which they capture prey simply by squeezing their jaws around them.
In videos of the dolphin with a camera on its side, however, the researchers could see the dolphin’s lips opening, its tongue retracting and its throat expanding. They think that all these subtle movements increase the space in the dolphins’ mouth and create negative pressure for sucking.
“With years of experience feeding dolphins, we have not noticed this lip movement,” the researchers wrote in their paper. “Instead of catching fish in a ‘claptrap’ of their toothy beak, the dolphins seemed to mainly suck the fish.”
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