Haast was never great with details.

The stories he told about his early escapades were either vague or inconsistent. But one thing is certain: he was a snake kid from an early age, catching rattlers, garters, and copperheads in the woods near his Patterson, New Jersey, home and at summer camp in upstate New York.

When he wasn’t out in the wilds, Haast devoured every book he could find on snakes. His interest escalated to the point where he was keeping venomous species in a box tucked into a corner of his family’s apartment. Upon realizing  what he kept in there, his frazzled mother demanded he build a more secure enclosure—and never open it in her presence.

Seeing a rattlesnake kill its prey with a single bite sparked Haast’s particular fascination with the potency of snake venom.

Venom’s power had seduced thinkers as far back as Aristotle, but modern research only took off when scientists applied the concept of immunization to the toxins in the late 1800s. French researchers developed the first antivenoms in the mid-1890s. Not long after, Brazilian physician Vital Brazil created the first polyvalent snake antivenom.

During a visit to the United States in 1916, he stirred interest in this new therapy among the American press corps after saving the life of a snakebit Bronx Zoo keeper. The first American antivenom hit the market to much acclaim in 1927. Haast loaned a local pharmacist some of his snakes for a window display promoting the new product—right around the time he dropped out of school at age 16.

Though bored by school, the young enthusiast was obsessed with venomic innovations. He couldn’t shake the thought that scientists were just scratching the surface. “It seemed to me,” he told the New York Times in 1978, “that such a powerful, destructive force—like atomic energy—could be converted to many good uses if it were properly controlled.”

Haast sought an internship at the Bronx Zoo but was put off by the lengthy waiting list of applicants ahead of him. Instead, he hooked up with a traveling snake show and followed it down to Florida. After the show collapsed, he bounced for a few years between gigs in New Jersey and Florida, working as a speakeasy cashier, a construction laborer, and finally an airplane mechanic, while searching for a path back to working with snakes. Along the way he met a young woman named Ann Nocker, whom he married at 20 but only after warning her, he later said, that life with a snake man would be fraught.

A few years into their marriage, he angled his way into a job at Pan Am, which meant a pay cut but brought him to their Miami headquarters and the nearby snake-y Everglades. When the United States entered World War II, the military contracted his team to help with supply flights to bases around the globe—which Haast took as an opportunity to build out his collection. On stops, he would search markets. “While the rest of the crew was hitting the bars, I would be buying snakes,” he later recalled.

Haast’s crewmates weren’t wild about the cobras in his luggage, he added. Still, they tolerated him, and a few even agreed to help procure snakes. By the end of the war, he had built a de facto snake-smuggling cartel. He had also developed a plan to transform his unique and ever-growing snake collection into a career.

Until the mid-20th century, venom research was hampered by a lack of good samples. Most researchers either collected their own or relied on ad hoc networks of independent snake catchers and showmen. Informal and low-grade supply lines are still a common challenge, says Bryan Fry, a venom researcher at the University of Queensland, and often produce tainted, inconsistent, and generally unreliable raw materials.

Haast aimed to solve that problem by creating a centralized production facility where he would raise snakes on a standardized diet and in consistent environmental conditions, then collect their venom in a sterile lab at regular intervals.

He wasn’t the first person to develop such a vision. In 1908, Vital Brazil’s Butantan Institute established protocols for the systematic collection of venom from a massive snake farm—and even used public entertainment to subsidize its work. But several snake handlers and researchers stress dialogue between Brazilian researchers and American latecomers was rather limited at the time.

Haast raided his savings and sold the house Ann’s family had help them buy to purchase land and start building the Serpentarium in 1946. That was enough for Ann, who after years of weathering Haast’s whims, told him their marriage was over. With his funds running dry, Haast and their teenage son, Bill Jr, scrambled to finish the Serpentarium on their own. Haast later credited neighbors and his soon-to-be second wife and business partner, Clarita, with the idea of opening the facility to a curious public to generate revenue while he sought venom buyers.

The Serpentarium, which opened to visitors in January 1948, was a hit with tourists but a mixed bag when it came to snake husbandry.

Notoriously, Haast force-fed his snakes a meat-and-vitamin slurry of his own devising, at first using a rubber tube and later a modified caulking gun. Force-feeding, Hunter and other snake handlers say, is necessary for some species that don’t eat in captivity but unnecessary and even detrimental as a universal practice. It’s also definitively hard to watch. Haast kept smelling salts on hand to revive fainting tourists.

“If we knew then what we know now, nothing he did would have been done,” says Jim Harrison, a venom collector who grew up idolizing and later collaborated with Haast. But for all his criticism of Haast’s practices, Harrison acknowledges the man was doing his best to figure out how to run his operation on the fly, all in an era when keepers knew far less about venomous snakes’ behaviors and needs.

Haast gradually developed valuable new techniques for reducing the spread of disease among his snakes. He promoted novel methods for coaxing snakes into biting a membrane and releasing their venom into collection cups without any harsh “milking” of their sensitive venom glands. And he created a system for keeping the fluids fresh during long collection sessions.

“Venom is very thick, and it rolls down the glass very slow, and the smaller species give hardly none,” explains snake keeper Jack Facente, another Serpentarium alum. “So every fourth or fifth extraction, you put it in the centrifuge and spin it to the bottom before it dries out.”

Haast’s tools for the cheap, rapid freeze-drying of venom are still in use today. And most famously, he formulated his self-injection regimen, taking his first dose in September 1948.

By the 1960s, Haast had roughly 50 R&D customers, including the most prominent U.S. antivenom maker, Wyeth, which developed the world’s first coral snake antivenom with Haast’s help. Along the way, the Serpentarium became the hotspot for young folks interested in venomous reptiles. Many prominent U.S. herpetologists got their start there, and today most of the country’s venom suppliers are to some extent modeled on Haast’s lab.

To meet demand, Haast collected venom from up to 100 snakes per day. That lab work ate up most of his waking life; he relied on Clarita and his growing cadre of fans-turned-staff to keep the facility running and care for his snakes and a growing menagerie of animal attractions, including horses, iguanas, llamas, and at least one crocodile.

Meanwhile, Haast’s fame spread far beyond South Florida. In 1954, he became one of the few known survivors of a bite from a blue krait, a highly venomous snake from Southeast Asia. (Haast shunned the use of protective gloves during snake shows and venom collections, like many other handlers who to this day believe they interfere with sensitive work and put snakes at increased risk of injury.)

The blue krait incident generated a research paper, which suggested Haast’s self-immunization regimen might have afforded him some protections and thus merited study. It also drew the attention of a writer named Harry Kursh, at the time working for the pulpy magazine Argosy.

Haast was a good fit for Argosy’s audience, which loved a macho adventure tale. Not only was Haast a snake handler—he was a uniquely ballsy one. Hunter claims that, confident in his skills and the protection of his self-inoculation, Haast would intentionally drop snakes during shows to get a rise out of audiences. And whenever he got bit, he would calmly sit down and record his own symptoms for posterity.

Fascinated by this bold figure, Kursh kept in touch after publishing his story on Haast’s near-death experience, eventually penning a glowing biography in 1965. The book became a must-read for aspiring herpetologists and helped turn Haast into a niche subculture’s idol.

By the end of the 1960s, Haast had become a go-to expert on snake bites, even fielding a letter from the Bronx Zoo’s new curator of reptiles seeking advice on how to respond to cobra strikes. He was also a trusted source for U.S. military field-safety guides and even a collaborator on an NIH study on the role geographic variation plays in the composition of Elapidae snake venoms.

“I know of no one who understood the behavior of snakes better than he did,” says Ron Magill, a Miami zookeeper and Serpentarium alum.

If Haast had confined his work to these areas, he might be remembered fondly among scientists as a colorful but crucial link in the development of modern antivenoms and the discovery of unique biological compounds within venom. These molecules, University of Adelaide researcher Julian White points out, continue to yield exciting medicines—including weight-loss drug Ozempic, which is modeled on proteins discovered in Gila monster venom.

But Haast wasn’t satisfied with a bit part in the history of American herpetology. He wanted to pioneer his own venom research projects. Haast’s fans argue his work on this front, while flawed, truly helped people and catalyzed pharmacological innovations. Many prominent modern venom researchers take a dimmer view.

“I doubt the areas of ‘research’ and ‘treatment’ [Haast proposed] will be remembered in a positive way,” says White.

“I​’m not a man of formulas and equations,” Haast told Kursh, “but one of imagination and action.”

Haast believed he not only had an innate capacity to understand and engage with snakes, but a profound ability to grasp and improve anything. “If I really put my mind to it,” he once told Facente, “I think I could do open heart surgery.”

Haast’s third wife, Nancy, who started working at the Serpentarium as a 20-year-old assistant in 1966, recalls him spending spare moments between venom collections drawing sketches for devices to extract energy from the ocean’s waves or crack the science of perpetual motion.

When he read up on cobra bites years earlier, Haast got it in his head that their paralytic effects shared striking similarities to polio symptoms. He had a hunch the venom might hold some potential to treat the disease, although he couldn’t immediately articulate how. Eventually, he proposed that cobra toxins might block the virus from taking hold, a protective mechanism he would later liken to laying down a layer of varnish.

Many of Haast’s supporters claim he was the first person to propose using snake venom as a modern therapeutic. That’s untrue. As early as the 1910s, Western doctors concocted venom-based serums to treat epilepsy, to popular fanfare. And one of Haast’s first clients was a Baltimore drug company that had started developing a cobra venom–based pain reliver, Cobroxin, over a decade before the Serpentarium opened. Haast’s specific vision of venom’s curative potential was indeed unique. Still, it was just an idle idea, until Haast met Murray Sanders at the University of Miami.

Today, Sanders is better known for his contributions to U.S. biological weapons research during World War II and for what he claimed was an unwitting role in covering up horrific human experiments Japanese scientists conducted at their Unit 731 research facility. But in 1949 he was respected for his work on polio and investigations of the interference phenomenon, in which one viral agent competes with and inhibits another, a la Haast’s varnish theory.

Haast was wary of experts, who he feared might ridicule him as an amateur. But at Clarita’s urging he eventually told Sanders about his idea. “Well, I suppose it’s worth a try,” Sanders replied, according to Kursh. “I guess we can spare three monkeys.”

In fact, they dosed thousands of monkeys, and many more mice, with “detoxified” venom concoctions—hours after injecting them with polio. Sanders secretly tested the same serum on polio patients at the university hospital, recording the injections as “vitamins” in patients’ charts. He saw potential in early results, but experience had taught Sanders caution. While the findings merited further study, he did not immediately publish them.

Haast, however, had a habit of taking personal experience and initial experimental results as definitive proof of his intuitions. That paper exploring how his self-immunization might have protected him against the blue krait bite? Haast presented it to Kursh as definitive proof of his broad immunity. And Sanders’s early findings? They were proof he had intuited his way into a viable treatment for polio symptoms—maybe even, he later insinuated, a total cure.

Haast was also impatient. He admitted to Kursh that he could have done animal trials before starting his self-inoculation regimen. But he opted against the time-consuming safeguard and started his injections without even taking the time to tell Clarita.

Accordingly, Haast urged Sanders to roll out a venom-serum polio treatment based on their initial results—or at least start publicizing their findings. Sanders refused, insisting on a deliberate approach. This, Kursh recounts, left Haast perturbed.

During a trip the pair took to New York in late 1950 to seek project funding, word of their research reached syndicated columnist Walter Winchell, whose breathless report on an imminent polio cure generated a wave of sensational coverage. Haast denied any role in the leak and initially followed Sanders in shunning the media frenzy. But within months, he started speaking to the press about the potential of their work.

Whether or not he planted the Winchell story, the incident opened a rift between Haast and Sanders, and their partnership gradually eroded. Sanders still bought venom from Haast and worked on the occasional project at the Serpentarium. However, by the time Kursh met the duo, he described their relationship as “strained to the point of enmity.”  

Despite that brief surge of popular interest in their work, by 1951 preliminary work on the Salk vaccine was well underway. In conversations with Kursh, Sanders suggested that the main bodies funding polio research decided Salk’s project was far more promising and threw their full weight behind it rather than fund an early-stage and less-substantiated venom venture.

Sanders, the veteran scientist, took this in stride and wrapped up his venom-and-polio research slowly over the next few years, finally publishing his findings in 1953 and 1954. Kursh meanwhile interpreted the polio project’s outcome as a lesson: science was petty and political. Outwardly, Haast was not as conspiratorial about the project as his biographer. But the saga planted a seed of doubt that would flourish over the coming decades.

Haast’s experience with the krait bite in 1954 left him with a few new ideas about how the paralytic symptoms associated with some venoms might overlap with a host of neurological conditions. Clarita, who cataloged his symptoms after he slipped into delirium, noted that he kept muttering, “This venom has got to be useful. It can’t affect every nerve in the body like this and not be useful. It must be.”

He sent vials of processed snake venoms to doctors far and wide, to see if they might test their efficacy in treating an array of conditions. At least one German doctor agreed, using a cobra venom serum to treat multiple sclerosis, but little came of that treatment.

Undiscouraged, by 1967 Haast had begun work on his own therapeutic, eventually dubbed PROven and advertised as a blend of cobra and krait venoms. He promoted it as a potential treatment for several diseases that affect the nerves, but primarily MS, and built a roster of doctors open to offering it to patients with few other treatment options. One, Haast’s longtime friend Ben Sheppard, tried PROven for his own rheumatoid arthritis, saw a change in his symptoms, and signed on as an enthusiastic prescriber.

Separately, Haast’s estranged partner Sanders pursued his own interest in modified-venom treatments, using one to treat at least 1,400 ALS patients out of his own now-independent clinic between 1972 and 1982. Many of the thousands of individuals treated by Haast, Sanders, and the small cadre of doctors they worked with reported positive results.

Then in 1979, Sheppard’s clinic came onto the FDA’s radar via news coverage of a shipping mix-up that misdirected a crate of kraits. Soon after, an inspector paid a visit to Haast’s lab. It was clean—perhaps cleaner and more professional than some collection facilities even today—but it was not in compliance with drug manufacturing regulations. Nor had Haast licensed his drug for experimental use or distribution.

The FDA, however, didn’t shut Haast down. By 1979 the biochemical potential of venom was clear—and exciting—even to cautious regulators.

In the 1960s, Brazilian researchers investigating fainting spells among banana plantation workers bitten by pit vipers identified peptides in the serpent’s venom with the power to dilate and relax blood vessels and drop a victim’s blood pressure. British scientists, privy to the Brazilians’ findings, had been working with this compound for years to develop a new hypertension drug. That then-ongoing research would soon lead to the creation of captopril, the first ACE inhibitor.

So regulators organized a series of meetings to walk Haast through how to make his lab complaint and offered to connect him with the National Multiple Sclerosis Society and other supporters who could help him find trial funding and operational support.

According to William Eaglstein, a physician and professor who studies drug development and the history and practices of the FDA, this is all standard for the agency. While the public views the FDA as a watchdog shutting down bad actors, the organization itself and the lawmakers who fund it measure success in terms of the number of new treatments it helps to shepherd onto the market.

“The FDA would be especially likely to do this,” Eaglstein said of the agency’s accommodations toward Haast, “when the potential agent is to treat a serious disease for which there is little treatment, such as multiple sclerosis.”

Haast, however, responded to this support with a lackluster research plan. Facente recalls him complaining that he didn’t have the resources to do what the FDA required. But Haast’s failure to bring his facility and research and reporting practices up to agency standards, several colleagues and friends agreed, may have stemmed from stubbornness as well.

“He didn’t seem to be really fond of medical doctors because of some of the criticism he used to get from some of them,” Hunter, the Serpentarium alum, recalls. Too often, they questioned Haast’s self-injections or the way he approached his work, which rankled a man long used to running his own show. He also doubted the value of regulators’ paperwork and often-theoretical concerns when weighed against his experience and intuition. He was the venomous snake guy, after all.

Around this time, Haast was also growing wary about sharing notes with established researchers. Friends and former employees say he and Nancy, now his right-hand woman, drifted toward insularity, even outright paranoia.

“He was very cautious of somebody that would come in and try to steal everything from him,” explains Facente.

As they waited for Haast to improve his operations, the FDA sent samples of PROven out for analysis. The tests, the agency reported, revealed that concentrations varied vial to vial. Alarmingly, they also exposed a secret third component: water moccasin venom, which can cause tissue necrosis, inflammation, and complications with blood coagulation. Haast called it his “secret ingredient—like Coca-Cola.” The FDA also reported that some batches contained venom from a fourth mystery species.

The FDA urged Haast to cease all PROven manufacturing and distribution. He was in potential violation of at least 16 federal laws and regulations, they explained, and venom and disease experts couldn’t identify a relevant biochemical mechanism at play in his drug. Haast shrugged off the warnings. When the appalled directors of Sheppard’s clinic shut down their operations, he brushed that off too, declaring them “just a bunch of stupid people, asses.” He had six other doctors in Florida still willing to distribute PROven on his behalf.

Sheppard, who died a month before the PROven revelations, had also been haphazard in prescribing the drug and recording its effects, investigators found. He never confirmed patients’ MS diagnoses and usually just noted whether recipients said they felt better in the following days or weeks. In reviewing his notes, the FDA found that the recovery his patients reported aligned with expected rates of spontaneous remission. Regulators also identified potential side effects Sheppard failed to report, including dizziness, headaches, swelling, and visual distortions—as well as one patient, a young woman from Texas, who died while undergoing PROven treatments.

More unfavorable news trickled out of Sanders’s clinic. A Baylor University double-blind clinical trial on his ALS serum—distinct but similar to Haast’s—found no benefits to patients beyond placebo. Sanders pushed back on these results, suggesting that the establishment was out to get him and his potent new treatment. But under increasing pressure from both the FDA and his peers, and with his own health failing, he wound down operations, administering his final dose of serum in 1982, and shuttering his clinic in 1983.

Haast, meanwhile, dug in. He ignored the FDA’s warnings, retained a celebrity attorney, and proceeded to get drubbed in court in 1981. The judge ruled that not only had he mislabeled and failed to license PROven, he had also made patently false claims about clinical evidence showing venom’s “extraordinary healing qualities” and misled consumers about his drug’s regulatory status. (Adding insult to injury, while the trial played out the FDA approved use of captopril, the venom-derived ACE inhibitor, for several cardiac and kidney issues.)

“There’s no benefit from it—absolutely no benefit,” Steven Shaivitz, a local neurologist who once prescribed PROven, told reporters after the case concluded in 1982. “It gets people’s hopes up. It costs money, and it may be dangerous.”

Yet the courts only barred Haast from distributing PROven across state lines until he could demonstrate compliance with FDA guidelines. In theory, this left Haast an opening to continue selling PROven within Florida or outside of the United States.

Slow and soft as this response may seem, Eaglstein says it too is par for the course. The FDA is a deliberate agency, and an overburdened one, he explains. Usually, its agents focus on pure compliance and distribution control, not on punishing people who defy their orders.

In early 1982, Haast voluntarily shuttered the entity he had set up to make and distribute PROven. But he refused to give up on the drug. Reports from that year suggest that he shifted production to Tijuana, via a new corporate shell, and continued to sell the drug abroad for at least a couple of years.

“It works. The FDA knows it works,” he told a reporter in 1984. “The FDA has found it is not dangerous at all. They just won’t tell the public that.”

That year, he closed the Serpentarium and moved to Utah. He had never loved the touristic side of the business and had talked about shutting it down as early as 1977, when a 6-year-old fell into the pit holding a 12-foot crocodile and died in the ensuing attack. Moving into the 1980s, visitation had fallen off, he explained, and he could now sustain himself with venom sales alone.

An old contact had given Haast a tip about a new innovation center near the University of Utah that might support venom-as-medicine studies. “Sounds like what we need,” Nancy told reporters after the move, “a progressive, scientific community, someplace which is aggressive and not afraid of new things.”

Haast later told an interviewer that he had found the state colder, stiffer, and more intolerant than expected. Reports from his time there make no mention of new work on PROven. They simply describe him collecting venom and filing patents on his collection gear until he and Nancy returned to Florida in 1990.

At 79 years old, Haast set up a fresh lab at their new home on the edge of Punta Gorda, to the consternation of nearby homeowners. “How would you like 1,000 poisonous snakes next to you?” one neighbor asked a reporter as Haast moved in.

The concern died down as it became clear Haast no longer had any interest in entertaining ticket holders on his lawn. However, he would entertain the occasional media spot. The aging handler seemed eager to show off his skills.

He also seemed eager to insinuate that, just maybe, the self-immunization he had practiced for so long wasn’t only protecting him from bites. Perhaps it was keeping him young. He made the occasional, unexplained claim that venom could potentially treat AIDS. And he expressed lingering regret that he never brought his venom cures into the mainstream. “This is my unfinished business,” he told an interviewer in 2008.

Meanwhile, a handful of new drugs derived from venom, most intended to treat cardiovascular issues, hit the market.

In 2003, Haast lost a finger to a snakebite which, combined with the damage from other bites, left him unable to confidently collect venom. That same year, Wyeth stopped manufacturing the coral snake antivenom Haast helped the company develop, citing low demand and high cost. At 97, he mused about his legacy. He never became a giant of the medical world, as he had once dreamed he would. Perhaps he did more good as a flight engineer than as a snake man?

“Will anybody remember me?” he wondered. “If they do, what will they remember?”

Most who knew and worked with Haast agree that, for all his flaws—his ego, stubbornness, and hostility to skeptical doctors and regulators—he was a compassionate man. He genuinely wanted to help others by promoting the real and potent medical potential of snake venom.

“He did not do anything that he did for money. That guy could live in a cardboard box with a jar of water and bread,” Facente says. “He really felt like he could help mankind.”

His lab was a template for modern collection facilities, and the venom it produced underpinned many fruitful studies. Haast’s friends describe an energetic, insightful mentor who made major contributions to the incremental work of venomic science and inspired generations of innovators in snake husbandry. He always took time to answer calls from researchers seeking his expertise; paramedics trying to track down antivenom; homeowners alarmed by errant snakes in their kitchens; and kids bit while playing in the woods. And though he claimed to do public-facing work only reluctantly, he was a great science communicator who changed the way people looked at venomous reptiles.

He demystified venomous snakes, says Fry, the venom researcher, “showing that they are not creatures of nightmare but magnificent creatures to be appreciated not only for their unique beauty but also their potential.”

Even his controversial endeavors continue to influence venom research, albeit in ways he never predicted or intended.

The publicity around his self-immunization eventually spawned a subculture of imitators. While Haast didn’t publish enough about his regimen for anyone to recreate it, much less encourage copycats, a few dozen admirers have crafted their own ad hoc protocols. Some are fellow snake handlers, seeking protection. Others believe the practice will boost their longevity. A few inject venom to chase the adrenaline rush of doing something extreme—or the literal high of venom toxicity. (Haast himself compared his krait bite to an acid trip.)

Although most experts believe the risks of the practice outweigh any potential benefits, in the 2010s several research teams launched projects probing these self-immunizers’ blood in hopes of developing stronger and safer antivenoms. An ongoing project involving the prolific self-immunizer Tim Friede attracted enthusiastic coverage in 2025. However, the overall results of this research have been mixed, and critics fear the attention encourages dangerous behavior.

That fear seems well-grounded when speaking to self-injector Steve Ludwin, who donated his blood to a since-canceled research project. Ludwin says the scientific spotlight drove him to recklessness, both in his regimen and behavior. “I was pounding in a lot of the snakes that Bill Haast was doing,” he says. “I’d take [an injection] and then go out skateboarding in London traffic. I thought I was invincible.”

For all his accomplishments, Haast seemed intent on tying his legacy to the fate of PROven, doubling and tripling down on its value despite reams of evidence suggesting otherwise. Instead of admitting the fallibility of his intuition and pivoting onto a more productive path, he crafted a narrative of grievance—of genius stifled by the ossified establishment and the horrors of red tape.

Haast’s most ardent fans seem equally intent on expanding this narrative rather than reexamining it. They’ve built a mythos around the great Snake Man who shook the world yet never got his full due. Nancy, Haast’s longtime champion, stands at the front of this charge. When asked for comment on this story, she sent a series of celebrity quotes on the nature of greatness.

“Some among the more learned class found it hard to comprehend that a ‘snake handler’ with no formal education could conceive of a cure for polio and a treatment for multiple sclerosis when they, with all their learning and resources, could not,” she wrote in a memorial to Haast.

Now 79, she still operates the venom lab. She has restricted access to his archival materials while she curates an official library of his works and account of his life. “Only when laid out in its entirety will people be able to fully comprehend and wonder at how one man could possibly have accomplished so much in one lifetime,” she says.