Standing outside Ken Darnell's house in the longleaf-pine country near Gordon, Alabama, last February, I could hear the rattling coming from a small building in the yard. I approached cautiously, having been warned. The noise grew louder. I turned a corner, and there, inside the building's screened porch, stood a sweaty man, wearing glasses and a ripped and bloody T-shirt. He was talking to a rattlesnake he called Little Girl Hot Pants, "because," he said, "of the way she coils herself." Little Girl was about five feet long, and she looked perturbed. "OK, sweetie," he said to the snake. "Time for your feed."

Darnell keeps 280 rattlesnakes, most of them eastern diamondbacks, in this unmarked building in his side yard. Little Girl was one of two he had named. (The other was called Shot in the Head, because Darnell had saved her from "a Mississippi blonde with a pistol.") A rat oozed out of Little Girl's gaping jaws – Darnell was force-feeding her – and onto her owner's considerable belly.

"I'm not as gross as this appears," Darnell said. "Or maybe I am. But there's a reason for it."

Darnell – who is 67 years old, has curly gray hair, a reddish face, and weighs around 260 pounds – carefully placed the snake back in her box. He turned, favoring me with my first direct look, as I stood nervously in a corner of the porch clutching my pen.

"Don't worry," he said. "I've got an almost perfect safety record."

Darnell lives 10 miles from Gordon, a town with no chamber of commerce, no movie theater, and, most notably, no hospital. There are far more snakes around than people, and they include the largest rattlesnake in the world. The eastern diamondbacks that weren't rattling on Darnell's screened porch, or in the Bioactive Inc. "laboratory" connected to it, slithered around in the nearby brush.

As I watched, Darnell unlatched a plastic bin and removed the lid, momentarily wielding it as a shield. He lifted out a beautiful olive-colored, eight-pound snake, using a jury-rigged golf putter with a ­C-shaped steel addition on the end. Standing back, he placed the snake on a foam pad. After a tense moment – the rattlesnake was free, the porch small – he pinned it behind the head with the hook, grabbed the head with his left hand, and positioned the body under his right arm. The snake's fangs fit over the side of a film-covered funnel, which it bit, releasing venom with a hiss. The funnel ran into a centrifuge tube on ice. Darnell's meaty thumb and middle finger depressed the two glands near the snake's jaw joint to get out all the milk. It was the venom that Darnell was after. It's worth a fortune, if you're willing to extract it.

"I love that sound," Darnell said of the hissing.Every two weeks, Darnell milks his snakes in three eight-hour shifts. His wife and dog stay clear. Gretchen hates the smell of the lab, and the dog, well, Sadie knows better. I am one of only two strangers Darnell has invited to stand on his porch as he milks. He doesn't like questions while he is working, especially ones that seek to understand the obscure economy in which he plays an important role. "You absolutely have no reason," he told me later in an email, "to inquire about my inventory and its value in monetary terms or my annual income unless you want to go into the venom business or are a government revenue agent." Darnell extracts approximately four-tenths of a gram of venom from each diamondback. The venom is processed in a centrifuge, freeze-dried, and – because it can fetch as much as $7,000 an ounce and because Darnell is paranoid – hidden. Later, when I emailed Darnell to ask where he kept the venom, he replied, "Please do not ask about this kind of thing again, or you will become persona non grata."

Darnell says he's milked some 300,000 rattlesnakes since he got into the business 35 years ago, probably more than anyone else alive or dead – death being where this work will usher you. He has milked up to 1,000 snakes in a single day. That day on the porch, he did 120.

"It's like anything else," he says of his work with venomous snakes, "except the means of production can kill you."

Darnell has been bitten by a rattlesnake only once, last year, on his left index finger, after an argument with his wife, who rushed him to the hospital – and he hasn't skipped a milking since. Given the number of venomous snakes he's handled, this record is extraordinary. Still, it's a touchy point. "You never ask a lawyer if any of his clients have gone to the electric chair," he said to me. "But you ask a snake handler if he's been bit? It's not polite."

Bill Haast, one of Darnell's role models and competitors in the highly specialized, subterranean world of commercial venom production, died in June 2011 at the unlikely age of 100. Haast is believed to have handled 3 million venomous snakes during his career, which began after World War II. His New York Times obituary stated, without discernible irony, that he died of "natural causes." In his later years, Haast couldn't pick up a snake at Miami Serpentarium Laboratories – a venom production lab in Florida – because his hands were disfigured from the 173 bites he had suffered. Along with Haast are men like Carl Barden, a 46-year-old former airline pilot who says as a kid, he dreamed of producing venom after he saw Haast on 60 Minutes. He has been bitten 11 times in his 20 years running Medtoxin Venom Laboratories in Deland, Florida. George Van Horn, who runs Reptile World Serpentarium in St. Cloud, Florida, is missing a few fingers.

"Any snake handler who's worth a damn," says Darnell, "is missing fingers."

By this logic, Darnell, who has all 10, isn't worth a damn. But, as he says, he is not a snake handler, a snake charmer, a daredevil, a hobbyist, or a reptile-loving weirdo.

"I'm a venom producer," he says.

He shows me an invoice he submitted to one of his clients: At $225 per gram of venom, he was owed $155,925.

Without question, the venom Darnell procures has a benevolent purpose – snake venom is a critical ingredient in medications that treat diabetes and high blood pressure, and help prevent strokes, among other illnesses and conditions – but his motivation is decidedly less altruistic. "An ounce of eastern diamondback venom," he says, "is worth far more than an ounce of gold."

Last July, one of Darnell's customers projected needing four kilograms of "EDB" and four more of western diamondback over the next 18 months. That single venom order, at $7,000 per ounce, could earn Darnell around $2 million and require him to perform about 25,000 milkings – many on his porch.Diamondback venom is a potent hemotoxin that kills red blood cells and causes tissue damage. It is also something that pharmaceutical companies and research labs need for medical research, in order to develop new drugs (and to make antivenin). But milking poisonous snakes is as dangerous and difficult as it sounds, and most pharmaceutical companies are not equipped to do it. Instead, they rely on a small network of eccentric, autonomous, and unaccountably brave men like Darnell. Consider the barriers to entry to this potentially lethal factory-and-farming job: finding a legal production location, finding buyers, liability, difficulty, danger, expense, danger. As someone who is both obsessive and entrepreneurial, Darnell may be the most successful of the bunch. "Down in Florida," Darnell says, "my two major competitors are having a tough time getting enough snakes to have a commercially viable group. I'm producing at least five times as much venom as they're producing together."

Every so often, snake men like Darnell will get a call from someone who's heard about the value of venom. "Hey, I'm going to start a venom lab," they'll say. "What do I do?" Carl Barden's response: "Get 500 venomous snakes, and take care of them for one year. Just keep them alive. Call back when the year is up, and then we'll teach you all about venom production." No one ever calls back. "Unless you have some borderline obsession with the animals," says Barden, "it is impossible to do this work. Most of us agree that it was never the money that got us here. It was all about the snakes."Ken Darnell grew up in Columbus, Georgia, the son of a furniture-store manager. After majoring in chemistry at Georgia Tech, Darnell went to law school at night. During his second semester, he came down with mononucleosis and dropped out, planning to return the next year. By then, though, he'd passed the bar exam, and soon he was practicing patent law in Washington, D.C., where he became a member of the local herpetological society. He'd always liked snakes.

He took a side job as a business manager of a venom laboratory in Baltimore, and his assignment was to bring back a few hundred snakes for someone else to milk. In his unpublished memoir, 'The Venom Gypsy,' Darnell writes, "Now here I am, a business manager of a venom laboratory who has never even picked up a venomous snake, and I either walk away from the 40 snakes glaring at me through the Plexiglas walls of that 'snake wagon,' or I save the venom for research."

Once he'd milked the first one, he was hooked, and soon Darnell decided that he could run a better venom operation than the Baltimore lab, which was about to go out of business. "I just kept it going," he says. "It's important that somebody does it.Venom saves lives."

People bring snakes to Darnell all the time. Some drop them off for free – in the back of a pickup truck, maybe, idling in his driveway – but most he has to buy.

"Ten a foot gets the guys interested," says Darnell. "They bring them here in the yard, honk the horn, and say, 'You want this snake?' They know good and well I do. They'll give me a five-foot snake, and I'll give them six feet for it. They think, 'Boy, we're really taking him.'"

Darnell also makes house calls. One day in February, I accompanied him on a trip to buy 23 EDBs from the Cobbs, a family in nearby Moultrie, Alabama. As we drove, I asked Darnell why he doesn't hunt snakes himself. "It's a waste of time when someone else can do it," he said.

Legally, eastern diamondback rattlesnakes can be hunted as early as November, when they retreat to the warmth of gopher tortoise burrows. In practice, though, not many people try to catch them before the end of deer season, in late January. Snake hunters don't want to get shot, plus most prefer to hunt deer. Warm weather can arrive by the third week of February in this part of Alabama. When that happens, the rattlesnakes leave the burrows and return to the fencerows, brush piles, briar patches, and junk heaps beside the chicken coops and hog barns – places where rodents live.

We arrived at the Cobbs' home in the afternoon. The snakes were piled in wooden crates in the driveway. After some small talk, Darnell removed and inspected each one, drawling his assessments. Tommy Cobb has been hunting snakes for 40 years. His preferred method, he says, is to thread a 20-foot hose into a burrow, place the free end to his ear, and listen for the telltale rattle. As he's telling me this, he reaches into the crate with his stick and pulls out a handsome member of the largest venomous snake species in North America. Its brown and yellow scales glitter like diamonds.

Betty Cobb, Tommy's wife, tallied up the total: one four-footer, two six-footers, the rest between five and five and a half feet. "We'll call it 120½ feet," Darnell announced, handing $1,205 to Tommy.

"Caught one once," said Tommy, "had just eaten a rabbit. Got me a white tie and put it around his neck, gonna make him keep it down. Well, I tied it too tight, and he died."

"That's cruel," said Betty, turning to me. "I told him that's cruel."

"A tourniquet on a snake," said Darnell. "Isn't that something."

"He was a fine snake," said Tommy. He paused, grew thoughtful, and then continued. "There's as many out there now as there's ever been. People clearing up so much land around here, they just moving 'em."

Perhaps, but last August, Bruce Means, an adjunct professor at Florida State University, along with three conservation groups, filed a petition with the U.S. Fish and Wildlife Service, asking to list the eastern diamondback rattlesnake as a threatened species facing a "decline toward extinction."It used to be that when people in the South and the Midwest got worried there were too many rattlesnakes around, they would hold a rattlesnake roundup. Imagine a bloody state fair: Snakes are captured and brought in by locals, often for a bounty. Prizes are awarded to hunters for the heaviest and longest snakes. Snakes are paraded around, prodded, harassed, and then, usually, butchered for their meat and skin. Three roundups take place in eastern diamondback territory: in Opp, Alabama; Claxton, Georgia; and Whigham, Georgia. The 82 snakes brought to the Whigham Roundup in January 2011 was the lowest number ever. That same month, the city of Opp offered a bounty of $8 per foot for rattlesnakes, to spur hunting. A local paper published the headline "there's gold in them there burrows."

Ever the opportunist, Darnell still goes to as many roundups as he can, milking the snakes – those about to be killed and those that will be spared – without having to pay the hunters.

"Mistreatment," says Darnell, "is in the eye of the beholder. Just having a roundup drives some people to mouth-foam regardless of the fact that money is raised for scholarships and venom is produced for an obviously good reason."

On January 28, Darnell made an appearance at the 52nd annual roundup in Whigham. Twenty-thousand country folk milled around Confederate reenactment tents, carnival games, face-painting booths, and reptile talks, buying leather belts, pitcher plants, novelty bras, marshmallow guns, camouflage eyewear, snake heads, and stuffed snakes. Inside the rattlesnake corral, a half-dozen Plexiglas tanks held about 20 snakes each. Wearing red suspenders, a black collared shirt, jeans, and glasses, Darnell lifted the snakes out with his special putter, measured, weighed, and milked them. He walked around so the crowd could get a closer look at the snakes that had already been milked. A man dressed in camouflage held his young daughter high in the air to see. She asked if the snakes would bite her. "No, sweetie," the father said. "They're probably more afraid of you than you are of them."