Babe may have mastered the art of rounding up sheep, but his achievement has been eclipsed by Hamlet and Omelette - young pigs which have turned their trotters to computers and video games.

In fact, a sheepdog's job woudl be a pushover for these large whites (the same breed as Babe), according to Professor Stanley Curtis of Pennsylvania University.

In earlier experiments, Curtis allowed pigs to set the temperature in their sties, revealing that they preferred cooler conditions than had previously been thought.

Now he hopes pigs will one day be able to tell their masters exactly what they think of their sties. "I want them to participate directly in the design of their accommodation," he said.

With the help of half-brothers "Ham" and "Om", Curtis has surprised scientists who have been working for decades with primates. The pigs have proved with their first forays into video games, that they are at least as clever as chimpanzees.

Curtis said: "These are the first pigs to have done this kind of thing."

Pigs showed a dogged persistenc when set a task, said Dr Sarah Boysen, one of Curtis's colleagues in the study. She said: "They are able to focu with an intensity I have never seen in a chimp."

The research, which started in January, is at an early stage and it is unlikely pigs will outshine chimps in terms of intelligence. Chimps, like humans, can show a "eureka moment", when they put two and two together, which is unlikely to be found in pigs, according to Boysen.

She said: "Pigs are creative and innovative, but there is going to be a limit. They are not going to sit down and chat with you, but chimps can't either."

Despite his findings, Curtis, who grew up on a farm, said he would continue to eat pork. But he admitted that others may never look at a bacon sandwhich in the same way again.

His work questions the snobbish assumption that humans are somehow special. Curtis said: "We knew chimps were also special, but we excused that because they were closely related."

Though comparisons to the brain power of other creatures are tricky, "there is much more going on in terms of thinking and observing by these pigs than we would ever have guessed."

Curtis's journey into the minds of pigs began after a discovery by Boysen, who works at the Ohio State University in Columbus and is renownedfor her work on animal numeracy.

She carried out simple tests with two Vietnamese pot-bellied pigs, Hamlet (no relation) and Helga and taught them to understand complex relationships between actions and objects.

The pigs were positioned in front of a ball, a frisbee and a dumbbell and told to jump over, sit next to or fetch any one of the three objects. Most of the time, they got it right. This was the first clue that pigs could understand relatively complex human commands.

The difficulty with this research is that pigs do not speak English and the Columbus experiment expected the animals to learn certain words. Curtis wants to reveal pigs' intelligence without having to rely on their linguistic skills.

This kind of work has been done on chimpanzees and other non-human primates by the National Aeronautics and Space Administration (NASA), which is interested in the concept of intelligence.

NASA had funded an effort by Dr Bill Hopkins, a renowned primatologist, to make chimps and rhesus monkeys computer literate. After initial scepticism, Hopkins agreed to advise Curtis on how to do the same for pigs.

First, the scientists had to check that Hamlet and Omelette could see what they were doing. It was thought that pigs were short-sighted. A test by an optometrist, however, revealed that the young pigs were long-sighted, but didn't need glasses.

Then it was necessary to design a pig PC. After some time persuading Hamlet and Omelette to use their snouts, Curtis found they liked grabbing the joystick between their teeth.

When Hamlet and Omelette first saw the computer, they seemed unimpressed. Curtis woudl climd=b into the pigs' "station" with them and direct their attention to the task at hand. Eventually, though, they joined the information generation.

Although it was not easy for the pigs to look at the screen and move the joystick at the same time, the tests revealed they had control.

"The first hurdle the pigs had to clear was to connect the movement of the joystick with the movement of a cursor on the screen", said Curtis.

Using sweets and a "dwoop" sound to reward correct behaviour, the pigs were trained to move a cursor so that it hit a coloured line. First the line was a border around the screen, so any persistent push of the joystick would be rewarded. Then the border shrank to a line and eventually to a single target square. It took a few hundred attempts for the pigs to master the joystick.

Curtis said: "These pige learnt the fundamental operation of a joystick-operated video game as quickly as the fastest chimps."

The scientists discovered pigs are much like primates in that they prefer certain directions - up and down, rather than from side to side.

"But then again, those are the movements they use when rooting for food," said Curtis.

Once the pigs coudl control the computer cursor, demands were put on their brain power. First theyw ere presented with a choice between two abstract icons, a scramble of straight lines of various colours and a jumble fo lower-case letters.

Moving the cursor to one would be rewarded with the "dwoop" and a sweet. Moving the cursor to the other would receive no reward and a penalty "nrrr" sound. "They have been doing that very nicley, learning which one gives the reward in a few minutes," said Curtis.

Similar results were reported by a collaborating team at Purdue, which did not carry out elaborate preparations but found the pigs were interested as soon as the scientist "put a computer game in a sow house".

Chimps spend much time distracted or grooming, but can play such games for an hour. Pigs are more focused than primates, but tend to burn out sooner, perhaps as a reflection of their success in getting food rewards.

Now other tests are planned at Purdue and Ohio to discover, for example, how long pigs can remember an icon that triggers a reward. Curtis has reason to believe they have a long memory - when Boysen took her Hamlet out of retirement after a three-year break, he coudl still tell the difference between a ball, a frisbee and a dumbbell.

Hopkins says he is impressed with the pigs - and admits they are the equal of his brightest chimps in some respects.

But why do pigs have to be smart? As a rule, scientists think brain power reflects the survival stratagems of a creature, a grazer being dimmer than an animal that hunts in packs and smarter than a bug that has only to soak sunlight to live.

Pigs fit this picture, says Curtis, citing their social hierarchy.

"They are very feisty and there are lots of challenges from pigs in the middle of the dominance order. The pig is what is called an opportunistic, omnivorous scavenger. This means they are always scanning their environment for their next meal."

Most intriguing of all, there has even been the suggestion that humans may have played a part in the evolution of the brain power of pigs.

Boysen said humans had lived with pigs for thousands of years and selective breeding may have helped to bring out the more social, intelligent aniamls.

And when released back to the wild, they do famously. "That tells you something about their real, raw abilities," she said.

- The Telegraph, London

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