Battery-powered hamsters which cost around £10 each have become the must-have toy for Christmas 2009.
Parents have been snapping up the Go Go Pets, known as Zhu Zhu pets outside the UK, as soon as they hit the shelves.
Jerry Storch, chief executive of Toys R Us, says they are a phenomenon on a par with Teenage Mutant Ninja Turtles, the smash hit of Christmas 1987.
There are five of the interactive pet hamsters, Mr Squiggles, Patches, Chunk, Pipsqueak and Num Nums.
Each responds to touch with squeaks and noise and can run about when set to "explore mode" or "choo and chirp" calmly when held.
They also react to accessories sold especially for them, including a toy house, bed and car.
Mr Storch said initial demand for the toys was so strong that Toys R Us did not list them in its Christmas toy catalogue to avoid disappointing customers.
“Word of mouth alone stimulated demand to the point that if we advertised it would only be bad for business,” he told the Financial Times.
The range was launched in the summer by Cepia, a small company based in St Louis, Missouri, in the US that was founded in 2004 by Russell Hornsby.
And Mr Hornsby intends to capitalise on the success of his toys, with plans to bring out a range of other animals.
“It’s not just hamsters,” Mr Hornsby said. “We are bringing out the clans: chipmunks, squirrels, hedgehogs, rabbits. We have all sorts of cute things coming.” Source