The wilds of Yellowstone National Park are a world of predators, scavengers and opportunists. In this vast and complex kingdom, two dominant predators reign supreme: the grizzly bear and the wolf. Size and power square off against speed and teamwork, as mighty grizzly bears contend with powerful packs of wolves for control of the food supply. Though these two fearsome hunters would normally rule their ranges uncontested, in Yellowstone they must share resources, or face starvation.

The Balkan Peninsula is notorious for being one of the great battlegrounds of history. And yet, it possesses another side unknown to many, where ancient forests and vast wetlands harbor pristine wilderness, and sheer cliff walls and desolate plateaus preserve a seemingly unchanged past. Indeed the Balkan Peninsula is home to a variety of regions that border on mythical. In Croatia’s Kopacki Rit Wetlands, land mines keep people away, but enable native wildlife to thrive. Further south, Montenegro’s Tara River carves through Europe’s longest and deepest canyon, and neighboring forests provide refuge to rare animals such as the Balkan Lynx. To the east, millions of birds flock to the Danube Delta to feast on swarms of mosquitoes. And at the west of the Balkans is Skadar Lake, a remarkable landscape of peaks and water.

Eels can be found all over the globe, in fresh and salt water ecosystems alike. But today, risk of over-fishing and the presence of dams and other obstacles that prevent eels from reaching their oceanic spawning grounds pose new threats to an animal that once roamed the planet alongside the dinosaurs. Artist, writer, and naturalist James Prosek explores the mysterious world of the eel.

Get an intimate look at the wildlife of Lapland, a region in northern Finland, the fabled home of Santa Claus and actual home of reindeer, great gray owls, wolverines, eagles, wolves, musk oxen, brown bears and more.

In Europe’s highest mountain range, discover how Eurasian lynx, griffon vultures, ibex, marmots and more face extreme seasonal fluctuations, from volatile thunderstorms and landslides of summer to avalanches and frozen temperatures of winter. In Part One of the miniseries “The Alps”, enjoy the Alps in spring and summertime as newborn animals grow up to face the coming brutal winter.

In the second and final part of NATURE’s miniseries “The Alps,” experience the hostile and bitter cold ecosystems of the Alps, shaped by snow blizzards and avalanches.

From early spring to late summer, follow new animal mothers through the trials of raising a family in the Rocky Mountains. Cranes migrate north to give birth, a bison mother protects her lambs from threats and young mountain goats learn to climb.

Young animals face new challenges as winter envelopes the Rocky Mountains, and spring means the end of childhood. A grizzly mom prepares her cubs for hibernation, a mountain lion raises her kittens and a bison calf must learn to survive the snow.

The enigmatic subjects of NATURE: The Urban Elephant, Asian elephants are losing territory to the inevitable process of deforestation. Industrialization all over Asia has hurt the mahouts, or elephant drivers, so that the trained elephants and their riders are being driven into major cities such as Bangkok to earn a meager living receiving donations and food from curious tourists.

Examines the variety of plants and animals living in the Sargasso Sea, a gigantic floating bed of seaweed near Bermuda.

This program features the Kogi tribe who live in the Sierra Nevada de Santa Marta in Columbia. They are pre-Columbian peoples, and consider themselves as the elder brothers of humankind. They insist that it is the modern world, the younger brothers, who are destroying the harmony of life on earth.

The activities of an elusive female leopard are traced over a two-day period on the hot plains of Africa.

TOOTHWALKERS presents extremely rare under-the-ice footage that reveals a complex and potentially dangerous side to this huge and often mysterious mammal.

THE FOUR BILLION YEAR WAR explains how both conflict and cooperation have helped shape the species that today populate our world. And it profiles the winners and losers in this epic evolutionary contest — from the massive dinosaurs who disappeared long ago to the humble bacteria that have survived for billions of years virtually unchanged.

Explores the selection process among different species for choosing a mate, whether it’s for life or just for the day.

Cats command our attention and our devotion. These fascinating creatures have been perplexing people for thousands of years.

For billions of years, life on Earth has been engaged in its own ETERNAL ARMS RACE, the subject of Part 3 of NATURE’s TRIUMPH OF LIFE. As predators became better hunters, their prey also evolved better defenses.

When animals are the subject, most people associate Australia with lovable koalas and leaping kangaroos. But an even more distinctive aspect of Australian wildlife is its abundance of animals -- from snakes and spiders to a host of marine life forms and at least one mammal -- that use venom to defend themselves, attack prey, and in some cases help digest food.

For centuries, the Tuareg people have braved the brutal Sahara to trade in salt, a precious cargo once worth its weight in gold. In this episode of AFRICA, Adam Ilius,salt production a young boy of nine, crosses hundreds of miles of desolate and dangerous desert on his first trans-Saharan salt caravan. After months of traveling, will Adam make it to Bilma, Niger to sell the caravan's salt for necessary food and clothing? Or will the shifting sands of the desert spell disaster for this tenacious group?

Scientists have discovered that natural poisons and venoms contain chemicals that can be used to create drugs for treating everything from chronic pain to cancer.

Patricia Clarkson narrates this look at the relationship between the sycamore fig tree and the tiny fig wasp, which is so small it could fly through the eye of a needle. The trees, which flourish in Kenya, produce fruit that provides nourishment to more wildlife than any other tree in Africa, but without the pollination the wasp provides, that might not occur. The documentary also examines other creatures that make the trees their homes, including gray hornbills (one of Africa's largest birds).

They are among the most reliable witnesses to a crime — expert in their testimony and bulletproof in their account. Yet they never utter a single word. They are the animals, plants, and insects that are being recruited by a special breed of forensic scientists to solve the most seemingly impenetrable of crimes.

"Jaguar: Year of the Cat" follows the predator in its native rain forests of Belize. Included: a pair stalk turtles, peccaries and armadillos; scenes of the habits of their animal neighbors, including toucans and ocelots.

A chronicle of hippopotamus life along the banks of Zambia's Luangwa River includes footage of males fighting over territory; females protecting their young; the hippo's importance to river ecology; and societal rituals involving the head male of the pod. Mark Hamill narrates.

Underdogs tells the poignant story of two misfit dogs whose lives were turned around by people who saw their potential for greatness.