Virtual pets have been unleashed in North America.

The hottest toy craze in Japan debuted at toy retailers in May, and should soon be a staple in every mass-market retail chain.

Bandai’s Tamagotchi, Tiger Electronics’ Giga Pets and Playmates Toys’ Nano pets are the three leading brands duking it out for supremacy in the virtual animal kingdom.

Inventory has moved briskly in stores at a traditionally slow time for toy sales. Retailers such as Toys ‘R’ Us and Kay-Bee report that they cannot keep up with demand, and are banking that virtual pets will bring in real dollars. The toys range from US$9.99 to US$19.99.

Virtual pets are tiny interactive electronic creatures that exist on LCD screens attached to key chains. Owners must take care of the pet in various life-like conditions walking it, feeding it and putting it to sleep while earning points in the process. The better you take care of it, the more points you earn. If you neglect it, the pet will . . . ‘go away.’

Tamagotchi, from Bandai, has been one of the hottest-selling toy items in Japan, and was the first to launch in the U.S. Gene Morra, vice president of marketing and sales at Bandai America, attributes the toy’s appeal to its close simulation of human-pet interaction. ‘It involves a play pattern of nurturing, and the gratification one gets from raising a real pet,’ he says.

Giga Pets, from Tiger Electronics, include six different pets, ranging from Compu Kitty to Digital Doggie to Baby T-Rex, licensed from The Lost World: Jurassic Park. Playmates’ Nano line allows owners to raise a baby, kitten or puppy in 30 days.

‘Virtual pets provide a totally unique play opportunity,’ says Marc Rosenberg, vice president of communications at Tiger Electronics. ‘[They] give kids responsibility [and teach kids] how something flourishes, or d’esn’t, depending on how you care for it.’

In Japan, over five million Tamagotchi units have been sold, and the products are in such demand that parents have paid up to US$600 for them. Although success in Japan d’es not guarantee success in America, retailers are so bullish on the toy that preorders have totaled six million units which translates to a potential US$50 million in sales. Toys ‘R’ Us CEO Michael Goldstein predicts that the toys will be this holiday season’s strongest seller. Fresh off of shortages of Sesame Street Tickle Me Elmo, stores do not want to be caught without inventory.

The products are being supported by multimillion-dollar promotional campaigns. Bandai has already received requests to license the Tamagotchi name, and is considering extending the brand via a TV or film presence.

Even though the primary market for the toys is kids age eight to 16 (Playmates is marketing its Nano line to girls age eight to 13), manufacturers believe that virtual pets will appeal to an older demographic as well. In Japan, the median age for Tamagotchi owners is 20, and initial sales patterns in the U.S. indicate a similar appeal to this age range.

If companies can continue to deliver new and interesting versions of virtual pets, and if kids, notorious for having short attention spans, will want to play with a toy that needs constant care, these items may be around for the long haul. But only time will tell whether virtual pets are this decade’s Cabbage Patch Kids or pet rocks.