Dolphin researchers in California discovered a unique addition to the diet of the aquatic mammal in August. What was originally a study to discover the capabilities of captive dolphins feeding in the wild resulted in the unforeseen discovery of a dolphin eating not one, but eight venomous sea snakes.
The National Marine Mammal Foundation in San Diego made this observation in a study that recorded the feeding behavior of several Navy-trained dolphins. The research was led by Sam Ridgway, a distinguished marine mammal scientist and veterinarian, who passed away in July. Ridgway and other scientists sought to find if dolphins that were fed frozen fish in captivity on a regular basis could successfully hunt and capture prey in the wild.
The researchers used GoPro cameras strapped to the dolphins to monitor the sound and sight of the aquatic predators. They recorded the dolphins successfully feeding on various types of sea bass and surprisingly—eight yellow-bellied sea snakes.
"I've read that other large vertebrates rarely prey on the yellow-bellied sea snake,” Dr. Barb Linnehan, director of medicine at the National Marine Mammal Foundation, told Business Insider. “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."
The researchers were initially skeptical that the animal recorded on the dolphin’s camera was in fact a sea snake. Dolphins have been known to play with sea snakes in the wild in “cat and mouse” like interactions, the study, published in PLOS One, noted. But no previous research shows dolphins eating snakes. The researchers stated that the dolphin’s life in captivity could have led to this unique observation.
“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 stated.
One dolphin, donned “dolphin Z” by the research team, was guilty of hunting and eating the small snakes. The researchers strapped a GoPro camera on top of the dolphin, directly behind its blowhole. A video of dolphin Z published by the research team shows the dolphin catching the sea snake using echolocation. The series of clicks used to locate the snake was followed by several head jerks while swallowing the snake before the dolphin let out a high-pitched “victory squeal.”
Additional video evidence shows dolphin Z struggling with one large sea snake before the prey escaped. Surprisingly, no signs of illness were found from consuming the venomous snakes, the researchers reported.
Feature image via Sam Ridgway. Feature video via US Navy/National Marine Mammal Foundation.
