A bear attacked and killed its caretaker at the home of a man who kept a menagerie of exotic animals and fell foul of regulators a few years ago by staging wrestling matches between bears and humans.

The bear in the attack south-west of Cleveland, Ohio was not one that owner Sam Mazzola had used for wrestling, officials said. His licence to show animals had been revoked, but he still kept dozens of bears, wolves, tigers, lions and perhaps coyotes.

The bear was out of its cage for feeding by 24-year-old Brent Kandra, "which was normal for this particular bear because the caretaker and the owner had been around it so much", Lorain county sheriff's captain James Drozdowski said. Mazzola used a fire extinguisher to force the bear back into its cage.

"We don't know whether something startled the bear or what prompted the bear to get aggressive with the caretaker," Drozdowski said.

Kandra died on Friday in hospital. The coroner's office said the tentative cause of death was "sharp and blunt injuries to the body consistent with a bear attack".

In comments to reporters outside his compound, Mazzola said he was the only witness. He declined to describe the attack, but said the bear was the victim's favourite.

"It's one that he played with constantly, every time he was here," Mazzola said. Whether the bear will be put down will be up to the victim's family, Mazzola said. "I want them to know that Brent loved the bear very much and I'm sure the bear loved him very much," he said.

Mazzola showed off a facial scar he got from an encounter with a bear and said he had 2,000 stitches from injuries suffered while working with animals.

"These are the things that happen when you deal with and love these type of animals," he said.

Mazzola, who filed for bankruptcy this year, had convictions for illegally selling and transporting animals.

The property held about seven to nine bears and 20 wolves, and possibly a lion and three or four tigers. Neighbours said he also kept coyotes.

Mazzola said in his bankruptcy filing in May that he owned two white tigers, two Bengal tigers, an African lion, eight bears and 12 wolves. The filing also listed 'Caesar the Wrestling Bear' as a trademark Mazzola held.

Mazzola used to offer people the chance to pay to wrestle a bear at the Cleveland Sport, Travel and Outdoor Show. People for the Ethical Treatment of Animals demanded that his licence to exhibit exotic animals be revoked.