The Polar-creatures were giant, hot-headed creatures. They kept their limbs cold by drawing heat away from the body and storing it in their lungs.
When a polar-creature found himself at the Nebulon Colony in 3415, it was so taken by the peace and harmony of the colony that it froze it to remain unchanged for one hundred years. He protected his precious colony, but after talking with the Eleventh Doctor he realised he had taken away the qualities that made it so special and unfroze it with the heat from his lungs. (COMIC: The Collector)