Gored by an elephant, charged by a lion and accompanied on two continents by flocks of reporters, artists and celebrities, Peter Beard was “half Tarzan, half Byron,” as the writer Bob Colacello once put it, an artist and photographer whose unrestrained appetites for drugs, alcohol and beautiful women gave him a reputation for being as wild as the animals he photographed.

An heir to tobacco and railroad fortunes, Mr. Beard abandoned a life of wealth and privilege to live at Hog Ranch, a 45-acre encampment outside Nairobi, where he embarked on expeditions to document the “wild-deer-ness” of East Africa. In photographs, collages and diaries that he turned into works of art, he chronicled the destruction of savannas, forests and wetlands, and the deaths of thousands of elephants and other animals who called those habitats home.

“What amazes me most,” he once said, “is that we are so willing to lose things that we can never get back — even further, we appear hellbent on our own destruction. It’s riveting.”

Mr. Beard, who split his time between Kenya and the East End of Long Island, was found dead April 19, not far from his home in Montauk, N.Y. He was 82, suffering from dementia and the effects of a stroke, and had been missing for nearly a month.

His family confirmed the death in a statement on his website, writing, “He died where he lived: in nature.” In an email Sunday, they said the cause of death had not yet been determined. A spokesman for the East Hampton police told reporters last week that neither foul play nor suicide was suspected.

At home in both the bush and the city, Mr. Beard went barefoot in Kenya, wore a saronglike cloth known as a kikoi and once surprised a Vanity Fair reporter when he emerged from his tent accompanied by “four or five” women. (“We were very cozy.”) In Manhattan, he partied at Studio 54, befriended Salvador Dalí and lunched at the Algonquin Hotel with artists Andy Warhol, Jonas Mekas and Jerome Hill, his cousin and mentor.

Handsome, energetic and disinclined to monogamy, he was married three times, including to model Cheryl Tiegs. Declaring that “the last thing left in nature is the beauty of women,” he was also romantically linked to women including Lee Radziwill, the sister of Jacqueline Kennedy Onassis, and Barbara Allen de Kwiatkowski, a model and Warhol associate who called Mr. Beard “one of the most beautiful men in the world.”

Mr. Beard supported himself partly through magazine assignments, photographing the Rolling Stones on tour and taking pictures of Naomi Sims on the back of a crocodile and Veruschka von Lehndorff roping a rhino.

But his primary focus was animals, including elephants and rhinos that he studied at Murchison Falls in Uganda; crocodiles that he researched at Lake Rudolph for the Kenyan government; and elephants he photographed by air and land, showing fields of bones that resembled abstract marble sculptures.

Mr. Beard had been obsessed with nature ever since he was a young man, taking outdoor photographs on a Voightländer camera. He made his first expedition to Africa in 1955, at age 17, and a decade later he published his best-known work, “The End of the Game: The Last Word From Paradise” (1965).

Significantly revised in 1977, the book captured what Mr. Beard viewed as the changing face of Africa, including the decline of the “great white hunters” and the animals they had long pursued. Sanctuaries such as Tsavo East National Park in Kenya had emerged as “overpopulated, overgrazed wasteland,” he argued, as elephants and rhinos struggled to find food and eventually starved by the thousands.

The book began “as a sort of corny homework assignment,” Mr. Beard said, written while he was still a college student at Yale. He had been fascinated by the work of Danish author Karen Blixen, whose 1937 memoir “Out of Africa” was published under the pen name Isak Dinesen, and later acquired Hog Ranch in part because it neighbored her former coffee plantation.

While his pictures featured animals that Mr. Beard championed in interviews and on safari, he positioned himself as something more than a conservationist, insisting that he was interested more in questions of existence, mortality and the fate of humanity than in issues of breeding and habitat management. “Conservation,” he told Vanity Fair in 1996, “is for guilty people on Park Avenue with poodles and Pekingeses.”

In elaborate collages, he layered his photos with handwritten notes, strands of horse hair, flattened insects, small bones, pebbles, cigarette butts and newspaper clippings. Many of his works were smeared with blood, from cows and other animals and sometimes from himself, and were developed out of enormous leather-bound diaries in which he chronicled his days and attached found objects.

Some of the diary pages were hung in gallery shows. Others were featured in his books, as documents that preserved or repurposed a past that he said he sometimes wanted to leave behind.

“I’m an escapist,” he told Vanity Fair. “I’m not a planner; I’ve never made a decision about anything in my life. The good thing about Africa is that you can escape forever. You can do what you want, without someone looking over your shoulder.”

He added, triumphantly, “I’m the most irresponsible person you ever met.”

The middle of three sons, Peter Hill Beard was born in Manhattan on Jan. 22, 1938. A great-grandfather, James Jerome Hill, had founded the Great Northern Railway, and a step-grandfather was tobacco magnate Pierre Lorillard V.

His mother “suffered from lack of education and the disease of conformity,” Mr. Beard said, and his father was a stockbroker who served in the Army Air Forces during World War II, leading Peter to spend part of his childhood on a military base in Alabama.

Mr. Beard studied at the Buckley School in Manhattan, the Pomfret School in Connecticut and Yale University, where he enrolled in a pre-med program before switching to art. By the time he received his bachelor’s degree in 1961, he had settled in Kenya.

He was reportedly on safari when he met Mary “Minnie” Cushing, a Newport, R.I., socialite whom he married in 1967. Their marriage ended in divorce, as did Mr. Beard’s second marriage, to Tiegs. In 1986, he married ­Kenyan-born Nejma Khanum. She survives him, in addition to their daughter, Zara Beard; two brothers; and a granddaughter.

Mr. Beard had his first major solo show in 1977, at the International Center of Photography in New York. That same year, one of his crocodile photos was included on the Voyager spacecrafts’ Golden Records, designed to introduce humankind to the cosmos. His photo, along with more than 100 other images and audio recordings selected by a NASA committee, is now traveling through space somewhere beyond the solar system.

His treatment of African animals and culture sometimes drew criticism, notably from the Somali model Iman, whom Mr. Beard claimed to have discovered. “He ‘loves’ Africa,” she told Vanity Fair, “but we always have an argument about what Africa really is. Is it the animals and the landscape, or is it the people? He has no respect for Africans, but it’s their continent — not his. For him, there are no people involved; they get in the way of his myth.”

While Mr. Beard maintained a charismatic and swashbuckling persona in interviews, he could also turn harsh and ugly, telling New York magazine in 2003 that homosexuality was “a societal ­illness of every single species in nature” and that Africans are “primitive” and “the only racists I know.”

But he remained a popular and near-legendary figure in the art world, with some of his works selling for more than a half-million dollars, according to a 2013 New York profile. His books included “Eyelids of Morning: The Mingled Destinies of Crocodiles and Men” (1973), with Alistair D. Graham; “Zara’s Tales” (2004), a memoir he wrote for his daughter; and “Peter Beard” (2006), a monograph published by Taschen.

Mr. Beard continued working even after an elephant speared his left thigh and crushed his ribs and pelvis, nearly killing him in 1996. He was airlifted to a Nairobi hospital, arriving in the operating room without a pulse, but said he held no hard feelings against the creatures he had spent so many years trying to save.

“I’m not a sentimentalist — I’m a dedicated fatalist — but I do feel I was very lucky,” he told People magazine. “I have no problem with that elephant hitting me. I just thank God it didn’t do a better job. Elephants are like humans. They are very smart, very logical. She owed human beings a real heavy debt, and she paid it to me.”