In 1959, the United States Air Force captured dozens of baby chimpanzees in Africa, transporting them to Alamogordo, New Mexico where they and their offspring were enlisted into in the space program.

NATURE's "Chimpanzees: An Unnatural History" explores the lives of these chimpanzees who were forced to endure a grueling life as the ultimate human stand-ins.

Brave the extreme conditions of Earth's southernmost continent for a close-up look at the varied penguins of the Antarctic.

Lynn Sherr hosts a collection of clips highlighting memorable moments from the program's first 25 years. Also: a tribute to the series' creator and host George Page, who died in 2006. Included: hatchling sea turtles on a Caribbean beach; barnacle goslings in the Arctic; a wildebeest defending her calf from wild dogs on the Serengeti; crocodiles attacking gazelles; chimpanzees saved from medical testing; a reunion of two elephants after 25 years apart.

With NATURE’S Rhinoceros, wildlife filmmaker Nigel Marven brings you face-to-face with the world’s five species of rhino, each struggling, with varying degrees of success, for their continued survival. For some rhinos, the future may rely on breeding programs, such as at the Cincinnati Zoo & Botanical Gardens, where Sumatran rhinoceros Emi is now nearing the end of her third successful pregnancy, having already given birth to Andalas and Suci, the only two Sumatran rhinos ever to be born in captivity.

The longest chain of mountains on the planet lies along the western edge of South America like an immense dragon - its tail falling into the freezing Antarctic Ocean, its head breathing fire 5,000 miles north. The Andes, home to the highest points outside the Himalayas, are remarkable not only for their volcanoes and their jagged peaks, the spines of the dragon's back; the niches they shelter are a world of extremes and hidden secrets. NATURE journeys the length of the Andes, passing through deserts and cloud forests, across glaciers and fjords, encountering the amazing creatures that call these habitats home: penguins and hummingbirds, pumas and flamingos, a deer only 12 inches tall, a tree-dwelling bear and much more.

More than 15 years ago, Martyn Colbeck began to document the lives of African elephants. He has grown close to elephant matriarch, Echo, and her close-knit family.

Conservationist Rom Whitaker searches for the last of the supersize crocodiles among the titans of the croc world: Nile crocodiles, saltwater crocodiles, and gharials.

With glaciers marking its tip, active volcanoes running along its spine, snow-capped peaks rising high above its range, both wet and dry tropical rainforests within its interior, and desert, lowland savanna and alpine tundra in between, the Andes is an extraordinary world of diverse terrain, extreme temperatures and multifarious wildlife.

Along her 9,000-mile voyage to nest, our loggerhead tour guide encounters hammerhead sharks, deep ocean tempests, and fishing nets.

Exploring how the domestication of dogs might have taken place, including the theory of biologist Raymond Coppinger that it was the animals themselves — and human trash — that inspired the transformation. The genetic analysis of Peter Savolainen of the Royal Institute of Technology in Sweden has placed the origins of domesticated dogs — and those of the first dog — in East Asia.

This episode details the explosion of the basic working dog types into the roughly 400 breeds known today; explores concerns about today’s competitive breeding and its effect on dogs’ health and well-being; and outlines dogs’ potential role in medical care for human beings.

The world of sharks is explored off the coast of southern Africa. Included: basking sharks; blue sharks; great white sharks; sand tiger sharks; short-fin mako sharks; and tiger sharks.

The Serengeti, in northern Tanzania, teems with big predators. But none compare to the lion. The Serengeti sustains one of the biggest lion populations in Africa: approximately 3,500 lions in 300 prides. But this pride, residing in the central Serengeti, is an exception. 22 lions in all: they are a Super Pride. Few lion prides reach Super Pride status. This phenomenon requires the right conditions. Plentiful prey and strong pride males are key to its success. But keeping cubs alive to maturity is the Super Pride's ultimate goal. Sometimes the greatest threats to a lion cub's life come from other lions…

Ohio's annual Ferret Buckeye Bash is the largest and most popular ferret show in the country. Hundreds of top breeders, seasoned experts and ferret enthusiasts pamper and parade their pets in a quest for prizes and prestige. Though these mischievous and often quirky creatures are unlikely show animals, the competition is intense. Tension is high but the tiny competitors don't understand all the fuss; they're too busy creating mayhem!

Follow two moose families as they negotiate the perils of wild and suburban Alaska. With encounters with predators and man a constant danger, life for a young moose is a daily battle for survival. A colossus of size, power and majesty, with an armoury unmatched on Earth, 'Mighty Moose' explores the hidden life of an icon of the Northern wilderness. In a savage landscape, the moose confronts daunting foes... and struggles against more insidious threats. And when it ventures out of the wilderness, it finds the obstacles of the human world both bewildering and deadly. Moose must increasingly share the forests, waterways, and now, sprawling urban centres with humans. As moose-human encounters increase, hungry moose invade backyards, parks and pools. Sometimes, encounters can be deadly - for moose and humans. Roadway collisions are at record highs, and rising fatalities drive car companies to develop and test moose-proof designs.