Are animals closer to humans on an emotional level than generally has been believed? The many scientists, researchers, wildlife photographers, and other animal experts interviewed in this Discovery Channel video answer with a resounding yes. They make their case in this 93-minute documentary, narrated by actress Sigourney Weaver, with stories of despondent dogs, grieving chimps, and lab rats who laugh when tickled. The first half focuses on happy bonds between mother and child, siblings, and animals and humans. The second half delves into the darker subjects of sadness and grief, offering astounding assertions such as elephants secrete a tearlike substance when upset and search dogs finding only corpses in the Oklahoma City bombing case needed treatment for depression

The giant panda has to be the best-known endangered species on the planet, thanks to the efforts of the World Wildlife Fund (among a host of others). In Save the Panda, National Geographic followed WWF-funded scientists as they made the first outside expedition into the People's Republic of China to study and, ultimately, help preserve these environmental icons. You'll see historical footage of panda hunting, the "panda-monium" that seized the Western world midcentury as a few dozen found their way into zoos, and the efforts of China and international organizations to help these animals deal with loss of habitat and a deadly bamboo die-off.

250 million years ago, long before dinosaurs roamed the Earth, the land and oceans teemed with life. This was the Permian, a golden era of biodiversity that was about to come to a crashing end. Within just a few thousand years, 95% of the lifeforms on the planet would be wiped out, in the biggest mass extinction Earth has ever known. What natural disaster could kill on such a massive scale? It is only in recent years that evidence has begun to emerge from rocks in Antarctica, Siberia and Greenland.

Despite their deserved reputation as fearsome hunters, African crocodiles are surprisingly vulnerable prey. This 50-minute entry into the National Geographic canon chronicles the lives of these 16-foot long, 1-ton beasts that Africans call "the animal that kills while smiling." When not taking down unsuspecting wildebeests come to quench their thirst on the banks of the Grumeti River in Tanzania, the female crocodiles spend a good part of their year nurturing first their eggs and then their young

Every year, every generation, human beings find new ways to express their strength. Some men possess the perfect combination of brute strength, raw power, pure speed, and bones of steel. Leading sports physiologists, biomechanists, medical experts, and material sciences engineers join Strongman to determine the secrets of a human being's fantastic abilities

Ex-Special Forces operator Frank Martin lives what seems to be a quiet life along the French Mediterranean, hiring himself out as a mercenary "transporter" who moves goods--human or otherwise--from one place to another. No questions asked. Carrying out mysterious and sometimes dangerous tasks in his tricked-out BMW, Frank adheres to a strict set of rules, which he never breaks. Rule One: Never change the deal. Rule Two: No names--Frank doesn't want to know whom he's working for, or what he's transporting. Rule Three: never look in the package.

In a remote part of southern Africa, a recent drought caused a quiet but significant upheaval. United by a common instinct to survive, scores of animals set out in search of water. The animals journey proved to be a life-and-death struggle that brought about momentous change to a pristine landscape of forest and river.