The Creatures are coming

They eat, they breed, they learn from their mistakes. Each is a highly advanced form of artificial intelligence.

"I Had worked hard for two years, for the sole purpose of infusing life into an inanimate body ... I had desired it with an ardour that far exceeded moderation; but now that I had finished, the beauty of the dream vanished and breathless horror filled my heart."

So writes Victor Frankenstein as his monster opens one yellowed eye; other humans, too, have long been fascinated by the idea of creating life. Millennium Interactive, a Cambridge-based software developer, has worked hard for four years to create Creatures considerably cuter than Frankenstein's monster. Available as a software pack for home PCs, they will be on sale in September.

These are the most advanced versions of artificial life in the entertainment industry, and are quite possibly a good evolutionary head and shoulders above the nearest academic equivalent - which currently has the brain power of a bacterium. Designed for entertainment, the Creatures could teach biologists a thing or two about evolution.

The Creatures run on a home PC. They are 2D, animated bundles of fluff with saucer-eyes and floppy ears - but don't let their schmaltz fool you. Each Creature is a complex mathematical model designed to be an accurate mimic of a simple biological organism. Dr Dave Cliff, from the School of Cognitive and Computer Sciences, at Sussex University, was asked to investigate Millennium's claim that the Creatures were a form of artificial life. Millennium said that the Creatures eat, drink, sleep, have sex, learn to speak, and are as unpredictable as a gerbil; like every kid's favourite pet, they also die. Dr Cliff says: "When I was first told what they'd done, I must admit I didn't believe it." What convinced him was the Creature's make-up - each one contains an individual neural net, a sophisticated piece of computer programming containing 3,000 neurons which act as a rudimentary brain, allowing the Creatures to learn.

The software pack consists of four to six eggs and an environment that is 12 computer screens wide and three screens high. The Creatures hatch from the eggs: their maximum lifespan is 40 hours of computer time (when the PC is switched off, they go into suspended animation). Owners have to grow plants for them to eat, and try and stop them from tucking into toxic toadstools. If they overeat they become obese, if they don't eat enough they get hungry and will eventually starve. They can also get drunk.

After they have been alive for four to six hours they start to show an interest in the opposite sex and will breed. The females are pregnant for two hours and then lay eggs, and although there is little parental care, they do play more with their offspring and other relatives than non-related Creatures. Breeding is like true genetic evolution. Each Creatures passes on half of its "genes" - parts of its programme - and some sections of the programme mutate. There are familial resemblances between offspring and parents: basic body design is a constant, but physical features, gait and various poses (such as the one adopted while sleeping) are genetically determined and will be inherited from the parents.

"You could do selective breeding," says Dr Cliff, "by taking two individuals which have traits that you like in the hope that the offspring will also show those characteristics, but you have no more guarantee that they will turn out to be better than their parents than if you were a dog breeder."

As well as having a primitive metabolism, they also have biochemical reactions which can affect the neural net - the brain - of the Creatures. Biochemicals, such as toxins and alcohol, cause whole clusters of neurons in their brains to be stimulated: whereas normally neurons, like our own, only signal to one other neuron at a time. Millennium calls this a hormonal system - for example, particular genes are switched on after the Creatures have been running for a certain amount of time, and this creates sex hormones which cause them to breed. The exact time at which these genes are switched on is inherited and hence will vary slightly between individuals.

The combination of hormones and their metabolic drive allows them to have simple emotions such as hunger, thirst, unhappiness and so on. These are not completely predictable because they are dependent on the interaction of up to 80 different types of chemicals. Millennium hopes to increase this to 250. All of these processes can be observed via the Health or Science kits.

The Creatures speak (in speech bubbles), understand simple words, and will learn tricks - but like any pet, whether they do them is not a betting matter. "It's life," says Toby Simpson, producer of the Creatures. "The Creatures' behaviour is almost totally unpredictable. We haven't specifically programmed any of their behavioural traits." It is this very unpredictability that is special - the Creatures have been caught playing and chasing each other, behaviour that was neither programmed nor predicted. Millennium says it doesn't know what to expect from the Creatures after they have been breeding for a few hundred generations. This idea of evolution in action is exciting for biologists. It will be possible to release the Creatures on to the Internet, and for biologist Tom Ray, this is a dream come true.

Dr Ray, who is currently at the Advanced Technology Research Centre near Osaka, Japan, was the pioneer of artificial life. A biologist who worked in the Costa Rican rainforest, he became frustrated by the fact that he couldn't see the process of evolution. He was determined to model life on his computer screen, but soon realised that creating various habitats and a multitude of species - a "digital game reserve" - would take more power than a supercomputer's. Dr Ray has just handed out 100 versions of a program called Tierra to computers linked by the Internet. In Tierra there are tiny software creatures that can determine how much memory and processing capability their host computer has and then they duplicate themselves until they have used up all the available memory. At this point, the program releases a "Reaper" which kills the oldest Tierrans. The habitats of the various versions of Tierra will differ depending on the host computer - a computer with little memory will be like a desert, and if there are few resources and a lot of Tierrans, then competition will be fierce.

The kind of questions that Ray wants to answer are: what regulates the ratio of host organisms to parasites? When does one species co-operate with another? Is evolution a gradual process or does it progress in fits and starts? Unfortunately, Tierra may be life, but not as we know it: the Tierrans are only as biologically complex as bacteria.

By contrast, the Creatures are much more sophisticated. Warner, which is distributing the software, estimates it will sell half a million copies to Britain and Europe before it begins to sell to America. This could result in the birth of a million new Creatures each week. If even a small proportion of them are allowed on to the Internet, who knows what the result would be - Dr Cliff is predicting the emergence of rudimentary language and culture in the absence of human intervention, and believes new species may evolve. Geneticist Dr Steve Jones, from University College London, agrees. "Evolution is just a mechanism that applies to living creatures, so there's no reason why the Creatures won't evolve, though I don't think they'll overtake the Internet."

"There could be applications beyond entertainment for cyber life," says Dr Cliff. "It's not sensible to download a Creature's neural net into a robot because their 2D world is so radically different from the real world, but parameters of the net could be used for some types of robots." Toby Simpson adds: "We could use this technology - a neural net capable of dealing with complex systems which can learn by itself from its own mistakes - in any mechanical job that would be better done by a human."

He gives the example of traffic lights: if a sufficiently motivated person were controlling a set of lights there would be no unnecessary waiting when there was no traffic, and situations like accidents could be dealt with more efficiently. The net the Creatures use could be adapted for this kind of application. Millennium is concentrating on making the Creatures more complex. "We've still got a long way to go," says Mr Simpson.

Currently their brains are not sophisticated enough to let them use tools, though Millennium hopes to rectify this. Before long, Stone Age Creatures may start chipping out hand axes at a Web site near you. !