As we can see in the provided information, certain types of dens are more resistant than others, those that are affected tend to be less stable and be in an area with less tree coverage, in many cases the fire generates the collapse of the roof, so we can say that forest fires can burn polar bear dens and collapse then or leave the highly damaged and unstable, in many cases propitiated by less frozen ground. This, in turn, will affect polar bears because female polar bears use these dens to raise the bears, their bears remain until next spring, without these refuges female bears can not preserve the necessary energy. Even more, if snow does not arrive on time the bears can be born in the outside placing the in a vulnerable situation.