Imagine dolphins in your local swimming pool. One reason this doesn't happen is that dolphins need space. In the wild, they can range up to 80 miles.

Even the marine parks that make a business out of captive dolphins and other large marine mammals, such as orcasOrcas are related to dolphins and are often called killer whales. This is because they were seen by sailors as fearsome hunters, who would even hunt other whales., are often criticised for being too small.

A robot, on the other hand, has no need for space. Nor does it need companionship or to be entertained.

With these differences in mind, Californian company Edge Innovations has unveiled a realistic animatronicA portmanteau word combining animation and electronic. A robot is animatronic when it is trying to represent a live creature. dolphin and recently took it for a dip in a local pool, to the excitement of many of the swimmers.

The company claims that its technology could help phase out captive animals from zoos and aquariums.

For many, the more we know about zoos, the more ethically dubious they appear. The kinds of entertainment people currently expect - looking at elephants, tigers or apes in their enclosures, or at dolphins leaping through hoops - may soon go the way of bear-baiting or cockfighting.

But what if animatronic technology could allow us to watch lifelike robot dolphins do tricks without ever having to put a wild animal in captivity?

Seeing these artificial animals could help foster a sense of wonder towards real nature, their advocates say, without doing any of the harm caused by keeping captive creatures.

Soon, you could see an elephant walking around a park without having to go to a zoo - let alone to Kenya.

It should even be possible to make imaginary or extinct animals. While the laws of aerodynamics mean we probably will not have flying dragons any time soon, we could have a chimeraAn ancient Greek monster with body parts from a snake, a goat and a lion. The word is now used to refer to any monstrous combination of things, and also any clearly imaginary fears. enclosure. There are already several parks featuring robot dinosaurs.

They are not at the level of realism of Jurassic Park quite yet. Still, as the technology for mimicking animal movements moves in leaps and bounds, the velociraptors could soon be leaping and bounding, too.

For some, however, such a cinematic world, while perhaps not as cruel as bullfightingThe practice of fighting bulls is banned in most European countries but is considered integral to Spanish cultural heritage., would still be a symptom of the same problem - treating animals as entertainment.

When the Tower of London menagerieA collection of animals for display. These have existed since there were people wealthy and powerful enough to collect animals. was open to the 18th-century public for the price of a cat to feed to the lions and tigers, nobody argued that it would develop people's sympathies.

A robot version of cheap entertainment, some critics suggest, might be bloodless, but it is not guilt-free.

Many people learned to love animals from playing with their toys; but as these toys become more lifelike, and more ubiquitousEverywhere., the debate continues as to whether will they bring us closer to real animals, or replace them.

Yes: Being able to walk beside an elephant or even a woolly mammoth will brighten people's days and will remind them of the majesty of nature.

No: Mechanical animals are yet another extension of human tyranny over nature. There is a sadness to replacing captive species with robots, rather than reflecting on our need to gawk at animals in the first place.

Or: They may not be a substitute for the real thing, but robot animals could provide a way of connecting people to nature. The way we treat captive animals now has to change, and robots are an exciting and creative way of doing that.