"Wildfires sparked by lightning near Canada's Hudson Bay are threatening the habitat of polar bears, encroaching on the old tree roots and frozen soil where females make their dens, a conservation expert on the big, white bears said on Thursday."

"Polar bears are more typically threatened by the melting of sea ice, which they use as platforms for hunting seals, their main prey. But those who live near Hudson Bay spend their summers resting up on shore when the bay thaws, living in dens dug in the frozen soil among the roots of stunted spruce trees.

Fires in this area are rare, said Steven Amstrup, a former polar bear specialist with the U.S. Geological Survey and now chief scientist at the nonprofit conservation organization, Polar Bears International."

Deborah Zabarenko reports for Reuters August 17, 2012. [2]