Temperatures in north-west Russia are so mild this week that they are disrupting bears' sleep in St Petersburg's zoo, local media say.
Leningrad Zoo's brown bear may have a really sore head
A zoo official told Interfax news agency that a black bear had woken from hibernation, while a brown bear had still not gone to sleep for the winter.
Temperatures have reached record highs of seven degrees celsius in some areas.
The unusual warmth, accompanied by heavy winds and rain, has melted river ice and caused flooding in the city.
Storms have been causing havoc across Northern Europe in recent days, and were described as the worst to hit the neighbouring Baltic states in 40 years.
Zoologists are monitoring the unusual behaviour of the bears, who are used to winter temperatures below freezing.
Itar-Tass news agency reports that wild bears, badgers and hedgehogs are also waking up from the long winter sleep in Belarus.
And in the western Russian region of Kaliningrad, spring flowers were already in bloom as temperatures rose above 10 degrees.
Meteorologists say temperatures are expected to drop at the end of the week, with more severe cold likely towards the end of the month.