The more we study dolphins, the brighter they turn out to be:
At the Institute for Marine Mammal Studies in Mississippi, Kelly the dolphin has built up quite a reputation. All the dolphins at the institute are trained to hold onto any litter that falls into their pools until they see a trainer, when they can trade the litter for fish. In this way, the dolphins help to keep their pools clean.
Kelly has taken this task one step further. When people drop paper into the water she hides it under a rock at the bottom of the pool. The next time a trainer passes, she goes down to the rock and tears off a piece of paper to give to the trainer. After a fish reward, she goes back down, tears off another piece of paper, gets another fish, and so on. This behaviour is interesting because it shows that Kelly has a sense of the future and delays gratification. She has realised that a big piece of paper gets the same reward as a small piece and so delivers only small pieces to keep the extra food coming. She has, in effect, trained the humans.
Her cunning has not stopped there. One day, when a gull flew into her pool, she grabbed it, waited for the trainers and then gave it to them. It was a large bird and so the trainers gave her lots of fish. This seemed to give Kelly a new idea. The next time she was fed, instead of eating the last fish, she took it to the bottom of the pool and hid it under the rock where she had been hiding the paper. When no trainers were present, she brought the fish to the surface and used it to lure the gulls, which she would catch to get even more fish. After mastering this lucrative strategy, she taught her calf, who taught other calves, and so gull-baiting has become a hot game among the dolphins.
Dolphins are clever in the wild, too:
In an estuary off the coast of Brazil, tucuxi dolphins are regularly seen capturing fish by “tail whacking”. They flick a fish up to 9 metres with their tail flukes and then pick the stunned prey from the water surface. Peale’s dolphins in the Straits of Magellan off Patagonia forage in kelp beds, use the seaweed to disguise their approach and cut off the fishes’ escape route. In Galveston Bay, Texas, certain female bottlenose dolphins and their young follow shrimp boats. The dolphins swim into the shrimp nets to take live fish and then wriggle out again – a skill requiring expertise to avoid entanglement in the fishing nets.
Dolphins can also use tools to solve problems. Scientists have observed a dolphin coaxing a reluctant moray eel out of its crevice by killing a scorpion fish and using its spiny body to poke at the eel. Off the western coast of Australia, bottlenose dolphins place sponges over their snouts, which protects them from the spines of stonefish and stingrays as they forage over shallow seabeds.
This earns a “wow”:
At a dolphinarium, a person standing by the pool’s window noticed that a dolphin calf was watching him. When he released a puff of smoke from his cigarette, the dolphin immediately swam off to her mother, returned and released a mouthful of milk, causing a similar effect to the cigarette smoke.
Their ability to learn a language is impressive:
By human definition, there is currently no evidence that dolphins have a language. But we’ve barely begun to record all their sounds and body signals let alone try to decipher them. At Kewalo Basin Marine Laboratory in Hawaii, Lou Herman and his team set about testing a dolphin’s ability to comprehend our language. They developed a sign language to communicate with the dolphins, and the results were remarkable. Not only do the dolphins understand the meaning of individual words, they also understand the significance of word order in a sentence. (One of their star dolphins, Akeakamai, has learned a vocabulary of more than 60 words and can understand more than 2,000 sentences.) Particularly impressive is the dolphins’ relaxed attitude when new sentences are introduced. For example, the dolphins generally responded correctly to “touch the frisbee with your tail and then jump over it”. This has the characteristics of true understanding, not rigid training.
I’m reminded of that damn bird, Alex the African Grey parrot, who was no birdbrain, and of Rico the Border Collie.
Maybe they talk submarine.