Dolphins have started lending a hand (or fin) to a small group of fishermen in Brazil.
The startling human-dolphin relationship occurs in Laguna, Brazil, where the bottlenose dolphins will herd mullet fish towards the fishermen and then – with a flick of their heads and tails – splash the water to let the men know their haul is ready.
The behaviour has been going on for generations, according to the local fishermen, and researchers have spent the last two years observing the behaviour – and trying to figure out what is in it for the sea-dwellers.
Helpful: The bottlenose dolphins of Laguna, Brazil, are helping fishermen complete their task – but why they should choose to help us is a mystery
Sheepdog style: The fish can be seen leaping out of the water as the dolphins slowly lead them to the nets
In this graphic, the white spots indicate the herding dolphins, the grey squares indicate the fish, and the black dots indicate the waiting boats
Waiting: The fishermen form a line as they wait for the dolphins to help
Dolphins at specific spots of the area help out – although only a third behave in this way
The snappily-named research paper, ‘The structure of a bottlenose dolphin society is coupled to a unique foraging cooperation with artisanal fishermen’, reports on the relationship.
The researchers found that, out of a population of 150 dolphins, 50 would help out while the rest would stay away.
The 50 helpers would act as sheepdogs, herding the schools of mullets – a small, silver fish – towards the lines of the fishermen.
When the dolphins came close, they would then slap their heads or tails against the top of the water, and the fishermen would have their catch.
The researchers noted that the 50 helpers seemed to be the most social dolphins in the pack, and would stay tightly associated with each other in the waves.
The researchers are also curious to find out how younger dolphins are trained to help out.
The haul is ready, so the fishermen throw out the nets, and catch their fish
And then the dolphins swim away… So long, and thanks for all the fish!
But what is in it for them? It remains a mystery. The dolphins do not get food from the process.
Are they staying on our good side? Is this the start of a new human-dolphin alliance? Or a Trojan horse before the dolphins turn against us?
Or perhaps they simply noted the struggles of the fishermen and, like true Samaritans, simple offered to lend a hand fin.
