MONTAUK, N.Y. — Taking chances has long been second nature to Peter Beard, a photographer and artist who spent decades living and working at his rustic tent camp in Kenya, where he documented both Africa’s natural beauty and its environmental decay.

Mr. Beard nearly died on a photography shoot in 1996 when he was trampled by an elephant and he was known to jump into waters to swim alongside crocodiles.

But when he disappeared two weeks ago from his home here, Mr. Beard, the adventurer who had honed his survival skills in the wild, was no longer the ageless, daring, physically robust explorer of the past. He was 82, incapacitated by dementia and walked slowly.

Though the police are no longer searching the nearby woods, the hunt for Mr. Beard, one of America’s most celebrated photographers, continues even as the mystery surrounding his disappearance deepens.