Five battery-powered robotic hamsters costing about $10 each have become the must-have toy of Christmas 2009, with parents in the US and the UK already snapping up supplies as soon as they arrive on shop shelves.

Zhu Zhu Pets, sold in the UK as Go Go Pets, are the hottest toy of the season, according to Jerry Storch, chief executive of Toys R Us, the retailer, a phenomenon on par with Teenage Mutant Ninja Turtles, the smash hit of Christmas 1987. "It is just phenomenal," he said.