A recent trend toward increasingly mild winters is disrupting normal hibernation patterns for many high-latitude and high-elevation species—and in some cases it may be a matter of life or death.

When animals hibernate they’re able to conserve the energy stored in their fat during periods when food is scarce. So when they are abnormally active, they risk using up their stored energy before they can replace it.

[Read](http://news.nationalgeographic.com/news/2007/02/070202-groundhog.html?source=rss “Read the Story”)(National Geographic)