Accidentally or intentionally released pythons and other exotic animals, such as parrots, reptiles, and lizards are inhabiting dry as well as wet habitats, and feeding on or competing with native species. Giant pythons are well-adapted for success in Florida, where the habitat is similar to their Asian home. Although they are non-venomous, pythons are among the largest snakes in the world, reaching up to twenty-six feet long. Their size and power makes them one of the top predators in Florida’s Everglades National Park, taking on even the alligators, and posing a threat to many of the indigenous and endangered species.

NATURE follows teams of scientists and hunters as they use their vast knowledge of snakes and their prey to uncover the impact of the pythons on the park’s fragile ecosystems. Herpetologist Shawn Heflick uses some innovative techniques to observe the mechanics of the snake’s bite, while scientists Stephen Secor and Skip Snow employ advanced technology to analyze the ways in which pythons swallow and digest animals that can be more than half their own body size. Watch as a wild python ingests an alligator whole.

Journey with NATURE as it investigates what comes next in the story of the Invasion of the Giant Pythons.

In Supersize Crocs, Rom takes viewers along as he sets off on his own hunt to find the last of the leviathans. Venturing to Ethiopia’s Lake Chamo, the riverbanks of India’s northern border with Nepal, and to the Adelaide River of Australian outback, Rom hits the hotspots of supersize croc habitats as he searches for signs of life among the brackish waters. Rom will share with viewers his insight and fascination with the cryptic world of crocs. Along the way, viewers will learn about ancient croc survival skills as well as how crocs are ideally designed to be the most successful freshwater predator.

Will he find his supersize croc among the three titans of the croc world: the Nile crocodiles, saltwater crocodiles and gharials? Tune in to find out.

To order a copy of Supersize Crocs, please visit the NATURE Shop.

Online content for Supersize Crocs was originally posted February 2007.

In the remote area of Death Valley National Park known as Devil’s Hole, six men suit up for a long day of desert exploration. But these explorers are swapping their dusty hiking boots and water bottles for neoprene wetsuits and oxygen tanks.

As NATURE’s Life in Death Valley reveals, the men are part of a specialized team of divers who assemble in this 40-acre pocket of Death Valley four times a year to monitor the population of the park’s most surprising desert creature: the critically endangered Devil’s Hole pupfish. Death Valley may seem an unlikely habitat for a fish, but this tiny species has managed to thrive here for thousands of years despite epic changes in its environment.

When summer temperatures spike to 120 degrees, it’s difficult to imagine Death Valley in an ice age. But twenty thousand years ago, the valley rested beneath a vast lake system where the ice-age ancestors of these pupfish swam. As the climate warmed, the lake dried and formed separate pools, and the fish that were once part of the same parent population began to develop unique characteristics in response to their individual environments, eventually evolving into several distinct species of pupfish.

But it’s the fragile Devil’s Hole species that has made the biggest waves throughout history, primarily due to the place it calls home. Located in southern Nevada, the “hole” itself is a fissure in the earth’s surface that split open 60,000 years ago to reveal an astonishing underworld: a water-filled limestone cavern. Ironically, beneath the hottest, driest place in the Western Hemisphere stretches a vast aquifer system. The opening at Devil’s Hole is one of the few places in Death Valley where the water from this system meets the surface.

“This is the only place on the planet where this fish exists naturally,” says Zane Marshall, head diver for the Devil’s Hole Pupfish Recovery Team. “Scientists have estimated that it has been in isolation here in excess of 25,000 years.”

Marshall’s team is part of a larger recovery effort that includes representatives from the National Park Service, the Department of Fish and Wildlife, and Nevada’s Division of Conservation. “This pupfish is the most restricted vertebrate species in the world,” says Marshall.

It was that exact notion that prompted President Harry Truman, in 1952, to protect the unique pupfish and its habitat by designating Devil’s Hole a disjunct part of Death Valley National Monument. For nearly two decades, the fish enjoyed a protected haven.

But by the late 1960s, development and nearby farming beyond the boundaries of the monument began to take a toll on the water levels in Devil’s Hole. As the pupfish do most of their feeding and spawning on an algae-carpeted limestone shelf just a few inches below the surface, a small drop in the water level was all it took to bring the fish to the brink of extinction.

What ensued was a bitter contest over water rights that pitted developers against conservationists and the federal government against a corporate farm. In the end, the fish reigned victorious. In 1976, the U.S. Supreme Court issued a landmark ruling that protected not only the fish but also their fragile habitat by specifically stating that water levels in Devil’s Hole must remain high enough to completely cover the spawning shelf. As a result of the ruling, development was halted, and the fish became one of the very first species to be protected under the Endangered Species Act.

Since then, Devil’s Hole has been cordoned off from park visitors by a chain-link fence that runs the perimeter of the hole. Only members of the recovery team are permitted access in order to perform quarterly counts of the fish. From 100 feet beneath the surface, the team works their way up in pairs, counting and measuring every fish they see. This provides them with an index of how the population is doing.

Despite 30 years of federal protection, recent counts suggest grim news: the fish’s population is once again plummeting. Linda Manning, a biologist for Death Valley National Park has been working closely with the Pupfish Recovery Team. “Right now we are very concerned because we recently had the lowest count in 32 years — only 123 fish,” she reports.

This time, however, the reasons for their decline are not so clear. Due to its protected status, study of Devil’s Hole has been extremely restricted. “We don’t yet understand everything that is going on in this system,” says Manning. “It’s a real puzzle. You wonder what the dynamics are. What’s impacting the fish? How are they making it? We’re just starting to get a handle on it, but there’s just still so much more to know.”

What they do know is that it is a harsh environment for a fish. The water temperature is 93 degrees Fahrenheit, food sources are extremely limited, and sunlight only hits the surface of the spawning shelf four months out of the year. “It’s pretty amazing that they’ve actually survived for thousands of years in this environment,” says Manning. “I just hope they can continue.”

In addition to conducting quarterly counts of the fish, the Park Service has installed monitoring wells near Devil’s Hole to keep an eye on the water levels, which have been dropping gradually over the past 14 years. Development and groundwater pumping in nearby Pahrump, Nevada, has long been suspected of affecting the water level in Devil’s Hole, though many Pahrump officials deny the allegations.

If the team doesn’t find a solution soon, the devastating effects may be far-reaching. “We definitely believe the pupfish are an indicator for the health of this system,” offers Manning. “When you start poking holes in the fabric of an ecosystem, over time it’s going to tear, and the impacts will be felt by everyone.”

Before that happens, the team will continue to do all they can to ensure the Devil’s Hole pupfish keep hold of their well-earned reputation as resilient survivors.

From 93 million miles away, the sun fixes its heated gaze on the scorched desert expanse of Death Valley National Park — the hottest, driest place in North America. But this is no typical desert. Here, breathtaking mountains rise two miles above sprawling salt flats, and mighty sand dunes dance alongside deep craters. Nowhere else is a land so exquisite in its beauty yet brutal in its extremes.

In this ultimate testing ground, the rules are simple — adapt or perish. Fascinating desert dwellers have ingenious ways to outwit Mother Nature in their quest to survive. Tiny antelope squirrels lay with their bellies to the ground in order to purge their bodies of excess heat, while jackrabbits use their long ears to cool themselves.

Whereas the animals appear to do everything in their power to avoid the extreme conditions of Death Valley, many visitors are drawn to the park for the sheer challenge. Top athletes flirt with their own mortality in what has become known as the toughest footrace on the planet, the Badwater Ultramarathon. This 135-mile road race snakes through the valley during the cruel blaze of summer.

In Death Valley, things are never quite as they seem. Beneath its parched surface lies one of America’s largest aquifer systems. Rare access into this astonishing, water-laden underworld brings viewers into a secret realm. Here, a team of biologists works to protect the critically endangered Devil’s Hole pupfish, a species that has lived in this watery cavern since the last Ice Age.

Explore the mystique and the majesty of the largest park in the continental United States on Life in Death Valley.

Online content for Life in Death Valley was originally posted September 2004.

The epic history of the Druids, one of more than a dozen packs now occupying the 2.2 million acres of Yellowstone, is documented in NATURE’s In the Valley of the Wolves, was produced and shot in High Definition by Emmy-award winning filmmaker Bob Landis.

On the Web site for In the Valley of the Wolves, you’ll learn how the successful reintroduction of Yellowstone’s apex predator has changed the entire ecosystem of the park, and about the threats that these majestic animals continue to face on their road to recovery.

Watch an online-exclusive video. In this video, Emmy Award-winning wildlife cinematographer Bob Landis discusses the making of the film, including the ideal circumstances for filming a predation scene; the importance of spending a vast amount of time in the field; the uniqueness of Yellowstone’s Druid wolf pack, and more.

To order a copy of In the Valley of the Wolves, visit the NATURE Shop.

Online content for In the Valley of the Wolves was originally posted November 2007.

For many decades, humans have harvested the horseshoe crab for use as fishing bait. Since the 1970s, we have also used horseshoe crab blood for medical purposes. But we may have gone too far. Horseshoe crab numbers have declined significantly since the early 1990’s. And, naturally, so did their egg numbers.

This is especially important to a small shorebird that is a global traveler of the most impressive kind. The red knot makes one of the longest migrations of any animal — a journey that takes it from one end of the earth to the other. To accomplish this feat, it relies on the eggs of the horseshoe crab. Without these eggs, the red knot is in danger.

In the film Crash: A Tale of Two Species, filmmaker Allison Argo tells the story of nature’s amazing ability to create fragile connections among the most unexpected creatures, and of our potential as humans to destroy those connections — or restore them.

To order a copy of Crash: A Tale of Two Species, visit the NATURE Shop.

Online content for Crash: A Tale of Two Species was originally posted February 2008.

Silence of the Bees is the first in-depth look at the search to uncover what is killing the honeybee. The filmmakers of Bees take viewers around the world to the sites of fallen hives, to high-tech labs, where scientists race to uncover clues, and even deep inside honeybee colonies. Silence of the Bees is the story of a riveting, ongoing investigation to save honeybees from dying out. The film goes beyond the unsolved mystery to tell the story of the honeybee itself, its invaluable impact on our diets and takes a look at what’s at stake if honeybees disappear. Silence of the Bees explores the complex world of the honeybee in crisis and instills in viewers a sense of urgency to learn ways to help these extraordinary animals.

Silence of the Bees premiered on PBS October 28, 2007.

Exclusive Podcast: In this podcast, scientists and bee experts featured in the program discuss the crucial role that honeybees, a “keystone species,” play in our economy and ecosystems, as well as bees’ fascinating social organization and what we can do to reverse the decline of nature’s pollinators.

In the 1960s, the bald eagle was on the brink of extinction caused by the pesticide DDT and other human pressures. Following their protection as an endangered species, bald eagles have come roaring back. But even in the best of times, life in the wild for these birds is a surprisingly tough struggle.

From the pristine wilderness of Alaska to the Upper Mississippi River Valley, American Eagle goes behind the scenes and into the nest to provide the ultimate bird’s eye view into the private life of an American icon.

The Steller’s sea lions that populate the Alaskan coastline are powerful, playful, and sometimes rowdy creatures who bump and jostle each other on land but acquire a sublime gracefulness in the water. They are also the subject of a strange and tragic mystery: Steller’s sea lions are rapidly disappearing from one of the last great wildlife strongholds of the world, and no one knows why.

Naturalist filmmaker Shane Moore, who has been working in the Alaskan wilderness for much of the past 10 years, brings a sense of urgency and new understanding to this puzzle in A Mystery in Alaska.

As scientists and environmentalists race the clock to find answers, pressure has been growing on Alaska’s fishing industry to suspend most of its pollock fishing, on the suspicion that it is robbing Steller’s sea lions of an important source of food. But new research illustrated in this film shows that a broad combination of factors could be responsible for the sea lions’ plight. Buy the DVD. This film premiered in May 2003.

Scientific research in Cuba on creatures such as the notoriously aggressive “jumping” crocodile, and the famous painted snails, paired with long-term ecological efforts on behalf of sea turtles, has been conducted primarily by devoted local experts.  Conservation and research in Cuba can be a constant struggle for scientists who earn little for their work.  But their work is their passion, and no less important than that of those collecting larger salaries.  NATURE follows these scientists as they explore the crocodile population of Zapata swamp, the birth of baby sea turtles, and the mysteries of evolution demonstrated by creatures that travel no more than 60 yards in a lifetime.

As the possibility of an end to the U.S. trade embargo looms, Cuba’s wildlife hangs in the balance.  Most experts predict that the end of the embargo could have devastating results.  Tourism could double, and the economic development associated with tourism and other industries could change the face of what was once a nearly pristine ecosystem.  Or Cuba could set an example for development and conservation around the world, defining a new era of sustainability well beyond Cuba’s borders.

Cuba: The Accidental Eden premieres Sunday, September 26, 2010 on PBS (check local listings).