Dolphins: The smart, sociable heroes of the sea

At the Institute for Marine Mammal Studies in Mississippi, USA, Kelly the Dolphin has been causing quite a splash. As part of the institute’s training programme, these much-loved marine mammals have been taught to pick up any litter that drops in their pool in order to swap it for a fish reward. The system was working well until one dolphin, known as Kelly, had other ideas. After finding a large piece of paper floating on the water, she hid it under a rock at the bottom of the pool instead of giving it to her trainer. She then tore off bits of the paper, getting a fish for each new piece she presented and thus maximising her fish quota. By hiding the paper in the first place, Kelly showed that she was able to delay gratification, and researchers have admitted that her scheme to split the paper into separate pieces shows quite sophisticated thinking on her part.

The shell trick

A recent study published in the scientific journal Current Biology shows just how resourceful dolphins can be. In Shark Bay, Western Australia, a whole pod of dolphins has been observed using empty shells as spoons. This activity, which has become known as ‘shelling’, involves a dolphin chasing a fish into a giant shell then trapping it by pushing its nose into the opening. After that, the dolphin will take the shell up to the surface and shake it to release the excess water. When the water has poured out of the shell, the dolphin tips the trapped fish into its open mouth.

Dolphins in legend

Our relationship with dolphins goes back as long as people have fished and travelled the seas. They were familiar in Greek and Roman art, where illustrations on coins, pottery and mosaic floors show leaping dolphins ridden by gods and demigods. The ancient Greeks believed them to be messengers of the sea god, Poseidon, and they were also sacred to the gods Aphrodite and Apollo. Killing a dolphin was considered a sacrilegious act. The Romans took their spiritual connection with dolphins one step further by imagining them to be guides who led the souls of the dead to the Islands of the Blessed. There have also been many stories that describe dolphins as rescuers of ships and drowning humans.

A dolphin hero

One such dolphin, nicknamed ‘Pelorus Jack,’ was famous for helping ships pass through the dangerous waters of Cook Strait, New Zealand, between 1888 and 1912. Despite the rocks and strong currents, no shipwrecks were ever recorded when Jack was present as a guide. Named after a nearby coastal area called Pelorus Sound, he was so important to shipping that he became the only individual sea creature to be protected by law in any country in the world. Mankind has long believed that dolphins are gifted with a rare intelligence and studies such as those carried out in the USA and Australia are helping us understand just how brainy they really are. No wonder we feel such a strong bond and sense of kinship with these lively, graceful and resourceful sea creatures.