After years of being neglected and abused, Fifi the bear finally hibernated after being rescued by The Wild Animal Sanctuary in Colorado.

As a cub, Fifi was taught to perform tricks alongside other bears. The zoo was reportedly shut down for multiple Animal Welfare Act violations in the 1990s.

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Since then, PETA says Fifi and the three other bears that were once performing at the zoo had been living in tiny, rusted cages that PETA compared to "a dilapidated doghouse."

Brittany Peet, a representative from PETA in charge of captive animal law enforcement, told InsideEdition.com that they intervened after being alerted to a suspicious advertisement giving away metal cages with one condition: whoever picks up the metal cages must also pick up the four bears that are in it.

"They were so well-hidden in the country that no knew even knew they were there," said Pat Craig, Executive Director of the Wild Animal Sanctuary. Craig also told InsideEdition.com that the couple were very old, and were probably waiting for someone to come by and put the bears down.

"Bears are so overpopulated in captivity that no one wants them," Peet said. "You literally cannot give them away, especially when you're talking about four geriactric bears."

She also said that in a recent study they conducted, there are over 1,000 bears living in captivity in the United States. They are often used in makeshift zoos or travelling shows, attracting people who are willing to pay for a photo-op with a baby cub.

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When Fifi and her cell mates were rescued and handed over to The Wild Animal Sanctuary in Colorado, the bears were in horrible shape, Craig said. Fifi had severe arthritis, her teeth had been filed down, and she had so little muscle that Craig described her as a "skeleton". The other bears were in similar shape.

"The first three or four steps [Fifi] took when we let her out of her transfer cage, she got into the water tank," Craig said, noting that Fifi had never been exposed to so much free space before. "[We knew] her spirit was going to soar really quickly, [even though] her body was going to take a while to catch up."

But, just five months later, Fifi's muscle developed to that of a normal bear, and her thin coat grew back to her natural color even though she was a "terrible white color" when they first rescued her, Craig said.

"You can really notice the difference hibernation makes," Craig said. In fact, the rescue bears were able to hibernate for the first time in their entire lives this winter.

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Peet told InsideEdition.com that most captive bears are not allowed to hibernate because the owners want the animals to be on exhibit year round. She adds, "All they had were tiny cages. I don't think they would have hibernated if they had the opportunity - it's not the right environment."

"The bears will never know deprivation again," Peet said, adding that PETA has trusted The Wild Animal Sanctuary in the past with their many other rescue animals.

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