Researchers in Bolivia recorded an unusual interaction between local rivers dolphins and an anaconda snake last year in the Tijamuchi river.
The two species would not normally interact but on this occasion a group of dolphins, some of which appeared to be juveniles, were seen carrying the snake through the water. At times the dolphins were unusually holding their heads out of the water.
It is unclear if the snake was unwell or already dead but the long snouts of the dolphins, filled with small teeth used to catch fish, would seem to be an unlikely threat for a healthy snake.
Anacondas belong to the boa family of snakes and catch their prey using constriction rather than venom. They spend a lot of their time in and around water. The Bolivian or Beni anaconda can grow to over four meters in length and weigh 35 kg.
It is unclear what the purpose of these interaction was - it may have been that older dolphins were teaching the younger ones about their environment and it is also known that dolphin will often play with objects and other animals they find.
River dolphins in Bolivia are a sub-species of the Amazon River dolphin. All river dolphins are under threat from human activities.
Read the scientific paper at the Ecology Society of America website