Is it a game, a hunting exercise or a strange sexual practice? Despite the efforts of researchers, the mystery remains unsolved.
Researchers have just published particularly astonishing work spotted by the New York Times. In their research paper, they describe a unusual scene; they have indeed surprised interactions between a gang of dolphins and an anaconda which left them confused.
The scene in question took place in August 2011, in the Tijamuchi River in Bolivia. A team of naturalists was documenting the exceptional biodiversity of the area when they came across Bolivian river dolphins. These are animals that are difficult to observe, as they are relatively rare and often discreet.
During their observations, the researchers noticed that these dolphins spent a considerable amount of time with their head above water; a suspicious behavior for these animals which largely prefer to remain immersed in the shelter of the river. In addition, the unusual movements of the group also challenged the researchers.
The distance did not allow them to distinguish all the details of the scene, but they still took the opportunity to collect a whole series of photos to try to decipher this unusual behavior.
Well it took them. Because by analyzing the pictures, they noticed that these 6 dolphins were not the only animals involved in this scene. Two of them thus spent long minutes carry a small anaconda in their mouths while swimming in sync!
Snack, toy or object of study?
Instinctively, the first instinct might be to consider that they were trying to devour the snake. But this hypothesis was quickly ruled out by researchers. Indeed, anacondas are part of what are called apex predators; a term reserved for species that do not have to fear the slightest natural predator. And the rest of this funny interaction proved them right, since the snake did not end up in the dolphins’ throats.
The researchers therefore suggested that it could be a simple game. It is common knowledge that dolphins are extremely clever animals, and their love for intellectually stimulating activities is no longer to be demonstrated; just watch a group having fun with unusually shaped bubbles in the video below to be convinced. And this is all the more true when these activities are carried out in a group, because the social dimension occupies a very important place in these species.
This last observation, in particular, prompted the researchers to formulate another hypothesis. Indeed, they noticed that some of the individuals were very young; so it could be a primarily educational activity. “They could have shown young people what an anaconda is, or even taught them hunting techniques”, explains the Times, citing the work of the team.
But none of these explanations has managed to win unanimous support. If the animal was alive, why on earth did the dolphins bother to go and rub shoulders with an apex predator that can easily weigh several tens of kilograms, even if it did not represent a threat to them? And if he was dead, what’s the point knowing that they obviously hadn’t planned to nibble on him?
A sex toy in spite of himself?
And the mystery deepened even more when the researchers spotted another, even more bizarre detail: by glancing at the side of the sexual organs, they noticed that the dolphins were particularly exhilarated. “It might have been sexually stimulating for them”, explains Diana Reiss, a marine biologist interviewed by the New York Times.
Although the wording may surprise, this is again a well-documented characteristic in male dolphins; these mammals indeed have a particularly active and diversified sexual life compared to the rest of the animals. “They often use their penises for tactile interactions” says Reiss, adding that he has already seen male dolphins attempt to penetrate the blowhole of a whale in an aquarium.
Moral of the story: none of the researchers interviewed by the NY Times failed to decide. At present, the motivations that prompted these dolphins to seize the anaconda remain still so mysterious. In any case, what is certain is that the person concerned must not have appreciated the experience. “I don’t think he had a good time”, concedes Steffen Reichle, one of the authors of the study.
The text of the study is available here.