Arthur Jones, a wild-animal enthusiast, filmmaker and entrepreneur whose Nautilus fitness machines helped to transform the fitness industry and the way ordinary people exercise, died on Tuesday at his home in Ocala, Fla. He was 80.

Mr. Jones died of natural causes, his son William Edgar Jones said.

Mr. Jones was a rough-and-tumble character who had six wives, a nearly lifelong smoking habit and an affection for exotic animals like rattlesnakes and crocodiles, which he kept at his farm, the younger Mr. Jones said.

He tinkered with exercise equipment for more than 20 years before creating his first Nautilus machine, called the Blue Monster, in the late 1960s. Mr. Jones presented the equipment at a Mr. America contest in California and started Arthur Jones Productions to sell the equipment. The company’s name was later changed to Nautilus, because the cam, or gear, that was crucial to the machine’s success resembled a nautilus.

Mr. Jones’ invention led to the “machine environment” that is prevalent today in health clubs. The company grew rapidly, and the machines helped to transform dank gyms filled with free weights and hulking men into fashionable fitness clubs popular with recreational athletes.