This program premiered May 13, 2000.

It was perhaps the saddest photograph Brian Call had ever taken. But it may help the Florida panther reach a happy ending in its struggle for survival.

Brian Call took this photo of a cougar that was struck by a car. In the spring of 2001, Call — a Florida wildlife illustrator and photographer — was driving home from a night of photography in a state park when he encountered a horrific sight: a young Florida panther, crumpled and silent in the middle of a rural highway. Stunned, Call climbed from his car to see if he could help, but it was too late. The panther had died minutes before; the body was still warm to the touch.

Soon, Call realized that the panther’s mother was hidden in some nearby trees, calling desperately to its lost daughter. Later, he would learn that the dead panther’s sibling, a male, was also killed that night by a car, not far away on the same highway.

Call knew he was witnessing a tragedy. As NATURE’s Trail of the Cougar notes, the elegant, powerful panther is Florida’s celebrated state mammal. But they are also one of the state’s rarest inhabitants, with less than 100 of the big cats remaining. Unfortunately, each year a few panthers lose their lives on the state’s highways, which increasingly hem in the cat’s shrinking habitat.

“I was quite upset, but I managed to pull myself together enough to document the scene,” Call recalled later. “The photos were the hardest images for me to take, but I made a promise to this panther that I would use them to help people become more aware of the hazards this endangered species faces.”

Indeed, Call’s photo has helped dramatize the threat that highways pose to Florida panthers. So did a memorial service he later organized at the spot. And while some major roads have fences and underpasses to help protect the cats, others remain dangerous byways. He hopes his efforts will help remind drivers to slow down to prevent tragic collisions — and convince government officials to step up efforts to protect the species.

Call discussed his interest in nature photography and his efforts on behalf of Florida’s panthers with NATURE:

NATURE: How did you get interested in nature photography?

Well, I’m originally from Massachusetts and I was always interested in nature. In the late 1980s, I went on a vacation to the Virgin Islands and learned how to use a professional camera. When my wife and I moved to Florida in 1991, I bought a nice camera. I had fallen in love with the Everglades; we didn’t have much money, but that was our escape. And I’ve been photographing there ever since, for the last 11 years.

Had you ever photographed a Florida panther before that night on the road?

No. But photographing a panther in the wild is the dream of every nature photographer in Florida. That night, I was on my way home from the Fakahatchee Strand State Preserve. When I found the panther in the middle of the road, my first reaction was to sit there and pat it. Then, I heard a chirping sound and realized it was the mother calling out to her cub. That made the whole scene that much more tragic.

It also really moved me to want to do something more than take photographs. I had always believed that using photography to bring nature back to the public and my friends would be enough. But at that point I decided it wasn’t. So my wife and I came up with the idea of holding a roadside awareness ceremony [in June 2001]. I was really motivated to bring this problem to the attention of people.

What was the ceremony like?

It was great. We put signs up along the road. I gave a speech and had some panther biologists give talks. There was a nice crowd and lots of media. Some passing cars even slowed down. But we stayed way over on the side so no one became a road kill themselves.

Signs on Florida roads alert drivers to cougars in the area. Is there any kind of sign marking the spot?

We couldn’t leave anything permanent. We tried, but the [highway department] couldn’t understand why we wanted a roadside marker for something that wasn’t human. They said it had never been done before. I didn’t understand. I mean, this is the state mammal of Florida, and it symbolizes the state’s wilderness. I thought it was worthy, but they declined.

Are drivers aware of panthers?

There are signs all over the place that say “panther crossing,” and there are some flashing lights and rumble strips. But I’m still amazed at how many people fly down those roads.

Has it changed your driving habits?

I always drove the speed limit anyway, especially out in wilderness areas. Sometimes it takes me forever to get home.

Are cars the major threat to panthers?

Road kills are a major source of mortality. But they are not the only thing killing them. Panthers also fight over territory and sometimes to the death, because there is not enough habitat for them. So my biggest thing right now is preserving their habitat. That is the number one way to protect the Florida panther and its future.

You are active with Friends of the Florida Panther Refuge. Can you tell us more about that?

We assist the U.S. Fish and Wildlife biologists out on the refuge [headquartered in Naples, Florida]. We promote their mission and undertake activities, such as tree plantings and open houses. Anything to help raise awareness about panthers.

Have you seen other panthers in the wild?

I am actually lucky enough to have seen a live panther in the wild. I was with a small group and one crossed a dirt road we were on. He was about 100 feet away. We saw him for about 4 or 5 seconds. We also found tracks that day and a kill site; the panther had killed some type of bird. It was a high point for my wife and me. So I’ve seen a live panther but haven’t gotten any photographs of one. But I’ll keep trying.

Got a ‘gator in the garden, and don’t want him there? Then call Todd Hardwick.

Hardwick, 40, is one of Florida’s three dozen licensed alligator trappers. When worried citizens call state officials to report a nuisance alligator, the state calls on experienced trappers like Hardwick to size up the situation and recommend whether the big lizard should stay, go, or, in some cases, be killed. In 2001, Floridians phoned in 17,000 alligator reports, resulting in the relocation or deaths of more than 5,000 alligators. Under state rules, problem alligators smaller than 4 feet long are typically moved into one of the state’s preserves, but bigger animals may have to be killed.

As Part 1 of NATURE’S The Reptiles series shows, Hardwick’s job requires equal measures wildlife biology, teaching skill, and brute force. Sometimes, he simply needs to educate a frightened homeowner about alligator habits.

Hardwick runs a successful business called Pesky Critters that responds to hundreds of calls a year on everything from problem possums to marauding monkeys. Some of his captures have ended up on his spacious 7-acre farm, which often holds 100 animals or more and sponsors educational programs. Hardwick recently chatted with NATURE in between calls for help.

How did you get involved in this business?

I’m a native Floridian and growing up, I spent my time running around vacant land catching and watching animals. I didn’t want to go to the mall and play Pac-man. I even learned how to catch small alligators. By the time I was in high school, I was catching problem animals in exchange for movie and pizza tickets.

I got a lot of ridicule. People would ask me: “What kind of a job is possum catcher?” I thought it could a good one. Increasing human population was causing loss of habitat, and when there are more people and less habitat there are going to be conflicts. Most people aren’t very good in hand-to-hand combat with an opposum. So I’ve been doing it for 22 years now, and have captured tens of thousands of animals. It’s not a job for me, it’s a lifestyle.

Where do alligators fit in?

Well, [catching nuisance] raccoons and opossums is the bulk of my business. But from April to July, I pretty much run around chasing alligators. During those four months, it is just crazy because it’s alligator breeding season. The weather warms and they become very active, and start looking for romance in all the wrong places. I’ll have 50 to 75 complaints at a time in my territory, which stretches 220 miles from Fort Lauderdale to Key West. And it just keeps getting busier.

That’s a big change from when alligators were considered to be threatened with extinction, isn’t it?

When I was young, the alligator was an endangered species. Today, we call them a nuisance. There are over one million alligators in Florida — it’s a tremendous success story. But while we were helping them come back, we weren’t stopping development. So there’s a big misconception about who has moved into whose neighborhood. I’ll go visit someone who’s screaming about an alligator, and I’ll remember the area as being a wetland five years before. So I remind them that that they are the ones who bulldozed the wetland. I want them to understand that they are the invader here, not the alligators. I’m almost an ambassador for the alligator.

When I’m out there, I do all sorts of education. One of the biggest problems is that people living in Florida are from everywhere except from here, so they don’t know how to behave in alligator country. [I remind them that] the number one problem is people feeding alligators. It conditions them and takes their fear away. But you can’t tell a mom that a 9-foot gator is not a threat to her toddler — it is. They are conditioned to hunt small animals that are low to the ground. Gators eat dogs so commonly in Florida that the state refuses to keep records.

How do you decide if an alligator needs to be killed?

The good news is that there is a clear process. If the alligator meets certain criteria [including size], whether it is a threat to people, property, or pets, then it may have to be killed. But even if I have to kill one of my favorite alligators, I realize we may be preventing a possible human fatality. It also benefits the rest of the alligator population. By preventing any attack we can save thousands of alligators. That’s because when an alligator grabs someone there is tremendous publicity. People panic and want every alligator in the area removed.

Have you had any close calls?

I’ve been hospitalized several times for bites from raccoons, possums, and skunks. But fortunately I’m very good at what I do and have only been bitten once by an alligator, and it was a very mild bite. But you can never drop your guard. Even a 6-foot alligator can easily drown you. My health insurance company was very hesitant to insure me years ago, but now if I go in and can show I still have ten fingers, I get a renewal!

How big was the biggest alligator you’ve caught?

It was 12 foot, 7 inches and weighed 425 pounds. I’ve also caught a 22-foot, 250-pound reticulated python. It had been turned loose in a state park, and grew over 10 or 12 years. Then it grabbed a raccoon and went under someone’s house. We pulled it out and zipped it into a sleeping bag. Then I got on a plane with it to California, to be on the Johnny Carson show.

South Florida is unique — it’s almost like an open-air zoo. All of these pets that people release don’t die, they thrive. I’ve handled animals from all over the world without leaving home. I’ve captured escaped mountain lions, stampeding buffalo, and several hundred monkeys (it’s one of my specialties). Anything you can think of has, or will be, loose down here. And I’ll be the guy chasing it.

Where are you headed now?

I’ve already got 2 raccoons and a possum in the truck. I’m heading to a golf course where a 10-foot alligator is supposed to be intimidating golfers. I told them they should just put up a sign up that says “alligator hazard.”

Divers find unseen world harboring strange ecology in NATURE’s Springs Eternal: Florida’s Fountain of Youth.

According to legend, Spanish explorers believed that a fountain of eternal youth bubbled up to the surface somewhere in the place we know today as Florida. In a poetic way, they were right.

Beneath Florida lie hundreds of miles of underwater channels and caves that comprise the world’s largest known system of springs. Largely unchanged since the age of dinosaurs, these springs shelter strange life forms, support improbable ecologies, and dot the land above it with outlets of water that once — before the expansion of Florida’s human population — was as pure as any found on this planet.

With its abundance of alligators, sunfish, eagles, great blue herons, and of course, the gentle and endangered manatee — to name only a few of the state’s better-know fascinating creatures — Florida is a wondrous ecological laboratory, even on its surface. Below the surface, however, is where the real surprises lie.

Follow divers into dangerous and unchartered channels never before seen in NATURE’s Springs Eternal: Florida’s Fountain of Youth.

To order a copy of Springs Eternal: Florida’s Fountain of Youth, please visit the NATURE Shop.

Online content for Springs Eternal: Florida’s Fountain of Youth was originally posted May 2000.

In the summer of 1521, the Spanish explorer Juan Ponce de Leon lay dying on a Florida beach, mortally wounded during a skirmish with a native tribe. Drawn by tales of crystal clear springs bubbling with glittering flecks of silver and gold, the aging adventurer had come seeking the legendary fountain of youth. Instead of finding immortality, however, the trip cost Ponce de Leon his life.

But the sparkling springs were no fantasy — as NATURE’s Springs Eternal: Florida’s Fountain of Youth shows. In an amazing underwater tour, Springs Eternal takes viewers down into Florida’s magical transparent pools, where toothy alligators lurk and lumbering manatees slumber. The filmmakers even follow researchers deep into the earth, diving into the dark and mysterious underground rivers that feed the springs.

Florida’s springs are home to many alligators.

Ponce de Leon named his landfall “La Florida,” meaning “land of flowers.” But Florida is just as famous for its springs, which spew out billions of gallons of fresh, cool water every day. The state boasts more than 350 gushers, one of the highest concentrations in the world. The reason for the watery bounty can be found underground, where porous limestone bedrock provides plenty of nooks and crannies for water storage. The bedrock, in fact, is riddled with flooded underground caverns.

Most of the wildlife action, however, is to be found in the remarkable pools and rivers formed by the springs. Shoals of fish drift in the lazy currents, including some oceanic species that swim up from the sea each winter to enjoy the warmer water temperatures. Rich carpets of rippling aquatic grasses carpet the sandy floor, attracting grazing manatees, the gentle marine mammals also known as sea cows. The springs are also known for a more ferocious inhabitant: the American alligator. Indeed, alligators are so common that Ponce de Leon’s fountains of youth might better be called fountains of tooth.

The large reptiles, which can grow up to 12 feet long, predate the dinosaurs. Having changed little in the last 65 million years, these living relics have managed to elude extinction. Only human exploitation has hampered their success. In Florida, for example, alligator populations plummeted due to spiraling demand for their leathery hides, which were made into everything from boots to wallets. Between 1930 and 1940, over one million alligators were killed in Florida alone. In the 1970s, however, stiffer regulations allowed populations to rebound. Today, they are quite common again, living proof of the power of foresighted conservation policies.

Springs Eternal gives viewers a front-row seat to alligator life, from the bellowing, splashy displays put on by males in search of a mate, to the gentle courtship that follows a first date. It also provides a fascinating glimpse into the enormous mounds of rotting vegetation that female alligators build to incubate their eggs. In early summer, the expectant mothers bury up to 90 golf-ball-sized eggs in their mounds, then stand by on a protective vigil.

About two months later, the eggs begin to hatch. The newborns call out in high-pitched peeps, alerting their mother to lumber over and scrape away the entombing material, allowing the babies to claw their way free. Moms may even help break open the eggs and tuck the young into their mouths for a trip to the nearby water. Typically, however, only half the eggs hatch, the rest having been eaten by predators, such as snakes and raccoons.

For the next six months, the hatchlings will stick together in groups called “pods” that are protected by the mother. The youngsters may stay in the vicinity of the nest for up to three years. But just two of every 10 newborns will make it to adulthood. The other eight will be snapped up by hungry neighbors, including sharp-beaked herons. Springs Eternal captures several of these long-legged wading birds on the hunt, stalking baby gators drifting unaware in the grass. The tough-skinned reptiles aren’t an easy meal. The herons must repeatedly shake and pound their prey against the water to break its bones, so that it will slide down their narrow throats.

Birds aren’t the only threat to baby gators. Hungry fish eat their share — as do other alligators. Even young alligators that have grown 4 feet long may fall victim to cannibals lurking in their neighborhoods. Still, enough gators survive their perilous early years to keep populations growing. And as more people flock to Florida, the two animals are bound to come into conflict. While alligators rarely attack people, they have been known to help themselves to pet dogs and livestock.

Sometimes, however, having a wild alligator on your property can be a benefit. Large gators, for instance, dig themselves sunning holes near lakes and rivers, providing a place for rainwater to collect. In dry years, farmers have discovered that these “alligator holes” are perfect natural watering holes for their livestock, saving them the work of building new ones.

Early explorers hacking their way across Florida’s bushy landscape sometimes returned with amazing stories of mermaids basking in sparkling waters — or hideous monsters patrolling the seas. As NATURE’s Springs Eternal reveals, however, these tall tales were inspired by one of the most remarkable inhabitants of Florida’s springs: the manatee, or sea cow.

Manatees are marine mammals, like dolphins and whales. But they don’t share a dolphin’s sleek shape. Instead, they are slow, bloated animals that look like a pig or hippopotamus set to sea. And like livestock, they graze on vegetation, such as sea grasses.

Around the world, there are four kinds of manatees, which are also known as dugongs or sirenians (after the “sirens,” or mermaids, of ancient lore). A fifth species, the Stellar’s sea cow, used to live off the coast of Alaska, but hunters drove it to extinction in 1768, less than 20 years after it was first described by shipwrecked Russian explorers.

The Stellar’s sea cow was easy to kill because it lived in shallow waters, and was slow and fearless — just like its modern-day Florida cousin. Indeed, people can often paddle right up to a manatee, especially when the creatures gather by the hundreds each winter in a few Florida springs, such as the Crystal River, featured on Springs Eternal. The manatees are drawn in from their ocean territories by the springs’ warm waters and bountiful crops of vegetation.

Unfortunately, the manatees, which like to swim just below the water’s surface, are vulnerable to fast-moving boaters, who often run over the animals without realizing what has happened. And the gentle creatures are also threatened by water pollution, which is causing Florida’s once transparent spring waters to become increasingly cloudy. Much of the pollution is in the form of excess nutrients, such as nitrogen fertilizer from lawns and farms, which can trigger unwanted blooms of algae and tiny toxic organisms. These blooms sometimes form a deadly event known as a “red tide.” In the winter of 1995, for instance, nearly 400 Florida manatees (about 20 percent of the population) died from exposure to red tide.

Luckily, people are taking steps to protect manatees. Florida is attempting to educate boaters to slow down in areas inhabited by manatees. And the federal government has established several manatee refuges, where the animals can winter without worry of disturbance. The refuges have also proved a boon to researchers. They have learned, for instance, that though manatees may look ungainly, they can sprint short distances at speeds of up to 15 miles per hour, though they usually paddle along at about 4 miles per hour. Scientists have also shown that manatees have well-developed eyes: in clear water, they can detect objects more than 50 feet away. And they have been able to collect data that suggests that manatees can live 60 or more years.

It’s too early to know if such information will help prevent the Florida manatee from following its Alaskan cousin into oblivion. For the moment, however, visitors to Florida’s remarkable springs can still see the gentle animals that gave rise to myths of monsters and mermaids.

“It’s the most awesome thing I’ve ever seen.” That is how K. Michael Garman, a cave diver and researcher featured on NATURE’s Springs Eternal, describes the Dragon’s Lair, an unusual cavern he is studying in Crystal Beach Spring on Florida’s west coast.

As Springs Eternal shows, the Dragon’s Lair gets its name from a remarkable layer of bacteria that grows suspended in the water, lying like a smoky cloud between a heavier layer of salty water and a lighter layer of fresh water. “Some days it is thin and wispy, other days it’s thick and looks like solid bottom,” says Garman, who has probed the Lair’s depths dozens of times along with his wife Sherry and other divers. But the cloud never ceases to enthrall him, he says. “Every time I turn the corner [into the Lair], I’m afraid it will be gone,” he says.

Exploring in the dark can be perilous.

Getting into the cavern network is no easy task, as Springs Eternal illustrates. Unlike most Florida springs, which exit on land, Crystal Beach Spring emerges from the seafloor of the Gulf of Mexico. To enter, divers must go offshore and swim down to the entrance, a narrow, rubble-filled hole barely big enough to squeeze through. But by shedding their equipment and dragging it through the opening, the divers are able to enter a mystical — and dark — world.

Garman, however, says the lack of light makes things more interesting. “I’ve never been bored in a cave,” he says. “When you are diving on a reef, you are often looking at just another fish. But in a cave you notice a lot more detail because you are focused narrowly on what your light is showing you.”

In Crystal Beach Spring, he’s found plenty to look at. There are blind crayfish, small crustaceans, and snails. And each room in the maze-like cavern has its own feel. Besides the Dragon’s Lair, for instance, there is Thunder Road, the cave’s main passage, and the Bacteria Room, which earned its name from the orange bacterial and fungal mats that line its nooks and crannies. Eventually, Garman, a graduate student at the University of South Florida, hopes to write a thesis on the cavern’s unusual food web, which is based on the bacteria’s ability to live on sulfur extracted from the sea water.

Such research is not for everyone. Cave diving is a dangerous activity that requires extensive training, Garman notes. New technologies — from brighter lights to more dependable breathing gear — have made the sport safer and easier, he says, but are no substitute for experience and good judgement. “We’ve had things go wrong, such as a light going out, where we’ve called a dive and exited the cave,” he says. “Sometimes, you just have to say: ‘The cave’s going to be here next week, and we can come back.’ It’s just the smart thing to do.”