The US space agency (Nasa) would like its rubber ducks back, please.
Ninety bathtub toys were hurled into a drainage hole on the Greenland ice in September - an experiment to see how melt waters find their way to the base of the ice sheet.
It was hoped the ducks would flow along subglacial channels and eventually pop out into the sea. They may still, but nothing has been seen of them so far.
