Dolphins that help humans to catch fish form tighter social networks

In the coastal waters of Laguna, Brazil, a shoal of mullet is in serious trouble. Two of the most intelligent species on the planet – humans and bottlenose dolphins – are conspiring to kill them. The dolphins drive the mullet towards the fishermen, who stand waist-deep in water holding nets. The humans cannot see the fish through the turbid water. They must wait for their accomplices. As the fish approach, the dolphins signal to the humans by rolling at the surface, or slapping the water with their heads or tails. The nets are cast, and the mullet are snared. Some manage to escape, but in breaking formation, they are easy prey for the dolphins. [embed width=”610”]http://youtu.be/sVinWYmu5lQ[/embed] According to town records, this alliance began in 1847, and involves at least three generations of both humans and dolphins. Today, there are around 55 dolphins in the neighbourhood, and around 45 per cent ...