Discusses the tundra ecosystem and the role of lemmings as a keystone species in helping to maintain it, describing the lemmings' place on the food chain and what would happen to the tundra if they were to become extinct.

"Welcome to the arctic tundra! As you hike along the frozen ground of this cold, dry region, the tundra may seem quiet and empty. But it is full of life, in the spring when migrating lemmings munch on spring flowers, and even in the winter, when fur-coated wolves, foxes, and hares dart and prowl through the snow. Summer and winter in the tundra, the hunt is on to find food-and to avoid becoming someone else's next meal. All living things are connected...

Examines the arctic tundra as an ecological niche and describes the plant and animal life supported there.

Describes the climate as well as plant, animal, and human life in the nearly treeless area spread across northern parts of Canada, Alaska, Europe, and Asia.