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Dolphin brain: Saving the smartest animal in the ocean

BY Per Ola and Emily D'Aulaire

31st Oct 2023 Animals & Pets

7 min read

Dolphin brain: Saving the smartest animal in the ocean
Scientists marvel at dolphins' intelligence, which allows them to speak to humans and each other, but fear for the future of these trusting ocean creatures
At Kewalo Basin Marine Mammal Laboratory in Hawaii, psychologist and laboratory director Louis Herman puts a dolphin through its paces.
Using hand and arm signals, Herman asks, "Is the ball in the pool?" The dolphin correctly presses a plastic lever for "yes." Herman signals it to push the ball to a hoop. It does.
Then he signals his pupil to do it again, but this time he removes the hoop. Herman expects the dolphin to be confused or, at best, to push the "no" lever. Instead, it carries the ball to the no lever and stops there. In effect, it is saying, "I can do the first part but not the second because the hoop isn't here."
Herman is astonished. "This is a totally untrained, invented response," he says. We never dreamed the animal would 'think' the problem through like that."
Some 5,000 miles away, in the warm waters of the Bahamas, marine biologist Steve Leatherwood watches a female dolphin approach his research schooner, the Jennifer Marie, chartered by Oceanic Society Expeditions.
One of many that have been returning to the site for years, the dolphin swims slowly around the boat, then stops where Leatherwood and an assistant are treading water.

A special friendship between humans and dolphins

Dolphin playing in water with young boy
While the two marine biologists watch in amazement, the dolphin gently nudges a brand-new calf towards them, then swims a few feet away and waits.
As Leatherwood later notes, "It's as if the dolphin were saying, 'People, this is my calf. Calf, these are people.' The more time we spend with these creatures, the more we sense they have a natural affinity for man."
Across the Gulf Stream at the Dolphin Research Centre on Florida's Grassy Key, Miami psychologist David Nathanson slips into the water, holding five-year-old Billy Rainer, who was born with Down's syndrome. At the tweet of a trainer's whistle, a dolphin named Aleta churns towards the pair.
Nathanson holds a picture of a playground slide up to the boy. "What is this?" he asks. Billy squirms in Nathanson's arms. "If you want to play with Aleta, you've got to say the word," Nathanson persists.
"Many scientists now consider dolphins among the most intelligent animals on earth"
"Slide," Billy blurts. On the quay above, Billy's mother applauds with delight. This is the first time Billy has ever identified the pictured object without being prompted.
As a reward, Nathanson lowers Billy on to the dolphin's dorsal fin for a quick ride around the pen. "There's a rapport between them I can't explain," Nathanson says. "The animals are gentle with him, as if they understand he's different. In turn, Billy becomes motivated to learn things."
In study after study, scientists are uncovering surprising new information about these mysterious mammals. Dolphins, they confirm, really do "talk" to each other, whistling "names" for themselves and others in their school.
They help one another when in trouble. Like bats, they use sound waves to "see," and can echo-locate a fist-sized object in murky water more than a football field away. Because of these and a wealth of other findings, many scientists now consider dolphins among the most intelligent animals on earth.

Mimicry as a form of flattery—and communication

Two dolphins playing in pool
To get a closer look at these amazing creatures, we spent a week on board the Jennifer Marie, with Leatherwood and marine biologist Pamela Byrnes.
One of our jobs was to provide entertainment for passing dolphins so they would linger long enough to be photographed and catalogued. Whenever we heard the cry "Dolphins!" we grabbed masks, snorkels and fins and slipped into the water.
The dolphins approached, as curious about us as we were about them, making chuckle-like squeaks that sounded like wet balloons being rubbed together. Weighing up to 21 stone and stretching seven feet from tip to tip, the animals circled peacefully, swimming within inches of our masks, observing us with dark, liquid eyes.
Like submarines pinging, they bounced sounds off our bodies to examine us. Their bulging "foreheads", called melons, contain fatty tissue thought to focus the dolphin's sound waves into a narrow beam. The resulting noise can reach 230 decibels—potent enough to stun fish.
Dolphins love to mimic, and ours quickly fell into that pattern. If we swam on our backs, they did too. If we dived, they followed.
"They realised the dolphin was trying to imitate a baseball game, raucous crowd noises and all"
This talent can be carried to extraordinary lengths. In one instance, a trainer blew a puff of cigarette smoke against the window of an observation tank. A young dolphin darted to its mother, nursed briefly, and spat out a cloud of milk against the glass. It was copying the "smoke."
At another aquarium, researchers placed a television set where a dolphin could see it. Not long after, they noticed the animal swimming in tight circles. It squeaked loudly, picked up a toy ball floating near by and flung it repeatedly into the air.
When the trainers hurried to the TV, they realised the dolphin was trying to imitate a baseball game, raucous crowd noises and all.
Even more surprising is the dolphin's ability to understand sign language. One of Herman's dolphins has mastered more than 50 gestural words, and even some grammar and syntax.
For example, it understands the difference between "bring the surfboard to the person" and "bring the person to the surfboard."
Says Herman, "We're still in the early stages of learning about the intelligence of these animals and our ability to communicate with them."

How dolphins speak

In one experiment two of Herman's colleagues showed a Frisbee, a ball and other objects to a dolphin, accompanied by a specific tone for each. The animal soon learned to imitate the sounds and associate them with their object.
Eventually the researchers were able to show the dolphin a Frisbee or a ball without the tones—and it would whistle the correct tone in return.
Scientists are learning how dolphins use this "speech" ability in the wild.
"Each dolphin," says Peter Tyack, an associate at Woods Hole Oceanographic Institution, "has its own 'signature' whistle." Among the 30 or so dolphin species that range world-wide, schools can be more than a thousand strong—and these "names" let one member tell others who and where it is.
Dolphins can also imitate the signatures of others. Combining its own whistle with that of another animal, a dolphin can in effect say, "Hey, Sam, it's me Bob, over here."
"Each dolphin has its own 'signature' whistle"
The length or pitch of the whistle can add further information: "Bob, it's Sam, over here, and I'm in trouble."
Notes Tyack: "As far as we know, humans and marine animals like dolphins are the only animals that modify what they say in response to what they hear."
"Sam's" trouble could be sharks, killer whales or, worse yet, a fishing vessel. Indeed, in the past three decades, commercial fishing has greatly diminished the world's dolphin population.
When fishermen discovered that yellow-fin tuna habitually swim beneath dolphin schools, fishing vessels began using the dolphins as markers to set their huge circular nets. In the process, they trapped the dolphins as well, and by 1990, millions of dolphins had drowned.

Dolphins under threat

Striped dolphin caught in fishing net underwater
As word of the disaster spread, private indignation forced the food industry to take action. In 1990 major tuna processors announced they would no longer buy from fleets that "set on dolphins."
While some foreign tuna fleets continue the practice, over 90 per cent of the US market is closed to such tuna.
Still, another big threat remains: the drift net. Every night in the North Pacific, hundreds of Asian fishing vessels put out these "curtains of death," each up to 50 miles long. Floating with the currents, they sweep up all sea life in their path. A United Nations resolution seeks to halt drift-netting completely by the end of 1992.
Despite the carnage, dolphins continue to be drawn towards people. Tales abound of dolphins pushing shipwrecked sailors to land. But most researchers are sceptical.
"Dolphins have to co-operate because they are air-breathing, warm-blooded animals in what for them is basically a hostile environment"
"The fact is," says Leatherwood, "dolphins like to play with just about anything that's floating in the water. Living at sea as they do, there's no way they could understand that people need to return to land. Besides, you only hear the success stories. Who knows how many people were pushed in the wrong direction?"
There is no doubt, however, that dolphins help one another. When a birth takes place, females gather to ward off sharks. Later, while the mother looks for food, they babysit the calf, swimming in a corral-shaped formation so the youngster can play safely inside.
The animals will even try, usually unsuccessfully, to rescue a calf captured in a fisherman's net. They also work together to gather food, circling a shoal of fish and driving it to the surface where the school can feed at leisure.
"Dolphins have to co-operate because they are air-breathing, warm-blooded animals in what for them is basically a hostile environment," says Tyack. "Think of it: they don't even breathe automatically. It requires a trip to the surface and a conscious effort for each inhalation and exhalation."

The need for a future with dolphins

Spinner dolphin swimming under water in ocean
The dolphin's intelligence and affinity for people led to Nathanson's innovative project at the Dolphin Research Centre. There, with the help of 15 dolphins, he works with children and adults who have Down's syndrome, hydrocephalus, cerebral palsy, muscular dystrophy, and head or spinal-cord injuries.
When Pam and Mike Glendenning of Verwood in Dorset read about Dr Nathanson's work, they flew to Florida with their son. Three-year-old Marc had never spoken and doctors could not offer a firm diagnosis for his condition.
During his fortnight at the centre in October 1990, he uttered the first coherent word of his life, "Tina," the name of one of the dolphins. "Contact with the dolphins seemed to help his confidence, and his ability to concentrate," say his parents.
"Is this, we wondered, what the world would be without dolphins?"
Meanwhile, those who are exploring the remaining mysteries of the extraordinary dolphin are increasingly concerned for its future. Already, 80 per cent of the spinner dolphins, a species noted for spectacular twisting leaps, have been wiped out. Tragically, other dolphin populations could suffer the same fate.
This was brought home to us a few years ago, while we were snorkelling off the Florida Keys. We had stopped to rest when, suddenly, the sea around us exploded with dolphins. A dozen of them leaped and twisted, showering us with spray. They were so powerful and graceful and exuded such joy that we roared with delight.
For about 20 minutes, they wove their magic about us. Then, as suddenly as they had come, they were gone. The sea now seemed empty and lifeless. Even the sun's sparkle on the waves appeared dull. Is this, we wondered, what the world would be without dolphins?
This article is part of our archival collection and was originally published in [December 1994]. While we strive to present historical content accurately, please note that circumstances and information may have changed since the article's original publication. Some individuals mentioned in the article may no longer be alive, and events or details may have evolved. We encourage readers to consider the context of the original publication and to verify any current information independently
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