In a single day, a dolphin that had been trained by the Navy hunted and consumed eight sea snakes that were known to be venomous. This is the first time that researchers have recorded a behavior like this.
The National Marine Mammal Foundation in San Diego, California equipped two bottlenose dolphins, who have been taught by the United States Navy to find mines using their sonar sounds, with GoPro cameras and attached them to the dolphins using straps.
During the filming of their video, the dolphins where on a break from their duties. The researchers were interested in observing the animals while they carried out their primary activity, which is fishing.
However, one of the dolphins went for a less conventional diet than the others. Her consumption of eight venomous yellow-bellied sea snakes was captured on camera throughout one day.
Before this research, which was published on Wednesday in the journal PLOS ONE, there was no evidence of dolphins eating sea snakes; instead, dolphins had only been seen playing with and releasing sea snakes. Consuming the meat of a poisonous snake may be very hazardous to the dolphins, so the behavior is very risky for them.
One of the videos that can be seen below shows a dolphin capturing a snake and then swimming about with it for a bit while continuously jerking its head to swallow the prey. According to the findings of the investigation, after that it lets out a high-pitched “victory squeal.”
“The dolphin clicked as it approached the snake and then sucked it in with a bit more head jerking as the flopping snake tail disappeared and the dolphin made a long squeal,” the study authors write.
In the video the dolphin merely allowed this sea snake to be seen for a fraction of a second before snatching it up:
The researchers at first couldn’t believe what they were seeing in front of them. They looked for other types of fish that would have given the impression of a sea snake when captured on video, but they couldn’t find any.
“I’ve read that other large vertebrates rarely prey on the yellow-bellied sea snake. There are reports of leopard seals eating and then regurgitating them. This snake does have the potential to cause neurotoxicity after ingestion and its venom is considered fairly dangerous,” Dr. Barb Linnehan, director of medicine at the National Marine Mammal Foundation, said to Insider.
According to the findings of the researchers, the dolphin did not exhibit any signs of illness after eating the sea snakes. They are unsure as to why she was seeking such dangerous prey; nevertheless, they believe that since she was born in captivity, she had simply never had the opportunity to learn any better.
“Perhaps the dolphin’s lack of experience in feeding with dolphin groups in the wild led to the consumption of this outlier prey,” the study authors wrote.
The researchers believe that she may have captured baby snakes since all of the snakes that she caught on video were relatively small. The dolphin did make an attempt to catch the bigger snake, but the snake managed to get away.
Images: US Navy/National Marine Mammal Foundation
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