Deep thinkers - The more we study dolphins, the brighter they turn out to be

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http://www.guardian.co.uk/life/feature/story/0,13026,989714,00.html

 

Deep thinkers

The more we study dolphins, the brighter they turn out to be. By Anuschka

de Rohan

 

Anuschka de Rohan

Thursday July 3, 2003

Guardian

 

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.

 

" Intelligence " is a term with many definitions and interpretations. It's

difficult enough to measure in humans let alone other animals. Large

brains are traditionally associated with greater intelligence, and the

brain of the adult bottlenose dolphin is about 25% heavier than the

average adult human brain. Generally though, larger mammals tend to have

larger brains, and so a more accurate estimate of brain power comes from

the ratio of brain size to body size - the " encephalisation quotient "

(EQ). While river dolphins have an EQ of 1.5, some dolphins have EQs that

are more than double those of our closest relatives: gorillas have 1.76,

chimpanzees 2.48, bottlenose dolphins 5.6. The bottlenose's EQ is

surpassed only by a human's, which measures 7.4 (Australopithecines -

hominids that lived around 4m years ago - fall within the dolphin range:

3.25-4.72). But we don't know enough about the workings of the brain to be

sure of what these anatomical measurements truly represent. Today, most

scientists share the view that it is behaviour, not structure, that must

be the measure of intelligence within a species.

 

Dolphins have invented a range of feeding strategies that more than match

the diversity of habitats in which they live. 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.

 

A dolphin's ability to invent novel behaviours was put to the test in a

famous experiment by the renowned dolphin expert Karen Pryor. Two

rough-toothed dolphins were rewarded whenever they came up with a new

behaviour. It took just a few trials for both dolphins to realise what was

required. A similar trial was set up with humans. The humans took about as

long to realise what they were being trained to do as did the dolphins.

For both the dolphins and the humans, there was a period of frustration

(even anger, in the humans) before they " caught on " . Once they figured it

out, the humans expressed great relief, whereas the dolphins raced around

the tank excitedly, displaying more and more novel behaviours.

 

Dolphins are quick learners. Calves stay with their mothers for several

years, allowing the time and opportunity for extensive learning to take

place, particularly through imitation. 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. Another dolphin

mimicked the scraping of the pool's observation window by a diver, even

copying the sound of the air-demand valve of the scuba gear while

releasing a stream of bubbles from his blowhole.

 

Many species live in complex societies. To fit in, young dolphins must

learn about the conventions and rules of dolphin society, teamwork and

who's who in the group. For these dolphins, play provides an ideal

opportunity to learn about relationships in a relatively non-threatening

way. At Sarasota Bay in Florida, Randall Wells and his team have observed

groups of juvenile male bottlenose dolphins behaving like boisterous

teenage boys. Using its head to do the lifting, one dolphin may even get

another dolphin air borne, actually tossing it out of the water. It's

unclear exactly what is going on. It could be play, but more likely these

are serious interactions that are defining social relationships.

 

Dolphins gradually build up a network of relationships, ranging from the

strong bond between a mother and calf, to casual " friendships " with other

community members. Wells and his team were the first to notice that adult

male bottlenose dolphins tend to hang out in pairs. The dolphins'

motivation for ganging together is under study but may involve ecological

and/or reproductive benefits. Dolphins may also form " supergangs " . Richard

Connor and his team in Shark Bay, Western Australia, discovered a group of

14 males. The supergang was a force to be reckoned with. In the three

years it was studied, it never lost a fight.

 

To keep track of the many different relationships within a large social

group, it helps to have an efficient communication system. Dolphins use a

variety of clicks and whistles to keep in touch. Some species have a

signature whistle, which, like a name, is a unique sound that allows other

dolphins to identify it. Dolphins also communicate using touch and body

postures. 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.

 

Lou Herman and Adam Pack taught the dolphins two further signals. One they

called " repeat " and the other " different " , which called for a change from

the current behaviour. The dolphins responded correctly. Another test of

awareness comes from mirror experiments. Diana Reiss and her researchers

installed mirrors inside New York Aquarium to test whether two bottlenose

dolphins were self-aware enough to recognise their reflections. They

placed markings in non-toxic black ink on various places of the dolphins'

bodies. The dolphins swam to the mirror and exposed the black mark to

check it out. They spent more time in front of the mirror after being

marked than when they were not marked. The ability to recognise themselves

in the mirror suggests self-awareness, a quality previously only seen in

people and great apes.

 

Not only do dolphins recognise their mirror images, but they can also

watch TV. Language-trained chimps only learned to respond appropriately to

TV screens after a long period of training. In contrast, Lou Herman's

dolphins responded appropriately the very first time they were exposed to

television.

 

Of course, an understanding of TV is of little use in the wild, but the

ability to respond to new situations has huge implications. In the

shallows of Florida Bay, Laura Engleby and her team have recently

discovered an ingenious fishing strategy. A number of the local dolphin

groups seem to use a circle of mud to catch mullet. The action usually

begins with one dolphin swimming off in a burst of speed. It then dives

below the surface, circling a shoal of fish, stirring up mud along the

way. On cue, the other dolphins in the group move into position, forming a

barrier to block off any underwater escape routes. As the circle of mud

rises to the surface, the mullet are trapped. Their only option is to leap

clear out of the water and unwittingly straight into the open mouths of

the waiting dolphins.

 

There is still much to learn about these flexible problem-solvers, but

from the evidence so far, it seems that dolphins do indeed deserve their

reputation for being highly intelligent.

 

Zoologist Anuschka de Rohan produced last month's Wildlife on One

programme, Dolphins - Deep Thinkers? This piece is based on an article in

the July issue of BBC Wildlife Magazine, available from newsagents or BBC

Wildlife Magazine Subscriptions on 01795 414718.

--

Kim Bartlett, Publisher of ANIMAL PEOPLE Newspaper

Postal mailing address: P.O. Box 960, Clinton WA 98236 U.S.A.

CORRECT EMAIL ADDRESS IS: <ANPEOPLE

Website: http://www.animalpeoplenews.org/ with French and Spanish

language subsections.

 

 

Something to think about: We believe that the Golden Rule

applies to animals, too. We don't accept the prevailing notion

that " people come first' " or that " people are more important than

animals. " Animals feel pain and suffer just as we do, and it is

almost always humans making animals suffer and not the other way

around. Yet in spite of how cruelly people behave towards animals

-- not to mention human cruelty to other humans -- we are supposed to

believe that humans are superior to other animals. If people want

to fancy themselves as being of greater moral worth than the other

creatures on this earth, we should begin behaving better than they

do, and not worse. Let's start treating everyone as we would like

to be treated ourselves.