Polar bears one of the largest and most dangerous hunters in the cold regions of the North. Their bodies are built for winter and they do best in the coldest areas. Unfortunately, polar bears are becoming threatened due to changes in the world’s climate. How does global warming affect polar bears? What must be done to save them? "The Footprint Reading Library" is the first non-fiction reading series for English language learners to present real-world stories in print, audio, and video. This series offers fascinating stories and facts from across the planet, and develops the language and skills needed to understand non-fiction writing. It offers a rich selection of engaging non-fiction, grouped into five themes: Incredible Animals, Fascinating Places, Remarkable People, Exciting Activities, and Amazing Science. One hundred individual readers are graded into eight levels - from Pre-Intermediate to Advanced. It ranges from 800 to 3,000 headwords.