Great Yellowstone Thaw

The vast expanse of the Greater Yellowstone area (which covers an ancient volcano) spans 34,000 square miles, contains an impressive variety of wildlife, rugged peaks, and valleys, and is an often forbidding landscape of intense cold and heat (temperatures can fluctuate 90 degrees in a single day). Hosted by Kirk Johnson, this three-part PBS-aired documentary focuses on Yellowstone's big thaw, a four-month period when bison, grizzly bears, elk, wolves, and bald eagles come together to mate, raise their young, and compete for food. Each animal has found a way to hang on and survive. Ground squirrels hibernate for up to eight months, storing food and body fat for the long sleep. The great gray owl is blessed with exceptional hearing, able to track prey under a thick coat of snow, and at distances up to 300 feet. Bison graze throughout the frigid winter, and hungry wolves hope to isolate a stray calf for a much-needed meal. Each season presents both challenges and opportunities: a mild winter may help bison, but leaves fewer carcasses for predators to feed on; forest fires can threaten plants and vegetation, while also opening up areas for seed distribution (an essential part of nature's regenerative cycle); and heavy runoffs from melting snow bring life-giving water, but also menace beaver lodges and animals trying to navigate streams. Climate change is affecting Yellowstone, with milder winters and retreating snow packs, and this will inevitably create animal winners and losers. An informative and beautifully-lensed nature series, this is highly recommended. Aud: H, C, P. (S. Rees)