March 2, 2015
The Norwegian University of Science and Technology (NTNU)
Norwegian mammals and birds have many different methods of surviving long, intense winter nights. A biologist reveals their secrets for survival.
For birds and animals that must live out in Norway's frigid winters, every second has to be spent finding enough food not just to survive the day, but also the long hard night.
Not every creature manages to survive -- it is not uncommon to find frozen birds in birdhouses after a winter cold snap.
Some creatures solve this problem by being inactive. Bears sleep and hedgehogs, bats, and the northern birch mouse all hibernate between October and April or May. But not every critter has this possibility.
Snow as an insulator
Surviving the cold is most difficult for small creatures -- large mammals and birds can go up to several days without food.
Small creatures tend to have a large surface area compared to their total body size, which means that their bodies loose heat quickly when the cold sets in. They also aren't able to store as much fat, which means less insulation and more heat loss. Surviving is all about preventing this heat loss.