Polar Bear, 'World's Saddest Animal,' Trapped in Argentine Zoo

Arturo the polar bear, confined to a zoo in sweltering Argentina, has been referred to as the "world's saddest animal," as he is falling into depression and exhibiting odd behavior, and animal lovers everywhere are campaigning to set him free.

For the last 20 years, 29-year-old Arturo has spent his days at a zoo in the western city of Mendoza, where temperatures have been known to reach well over 100 degrees Fahrenheit - a far jump from the Arctic temperatures of his natural habitat, according to The Dodo.

The miserable bear's existence didn't become a concern until two years ago when his companion Pelusa died and his condition worsened. He paces his confined cage over and over and lays face down, refusing to move.

"Arturo is basically the walking dead right now," Rob Laidlaw with the group Zoocheck Canada, fighting to free the unhappy animal, told CBC News.

"He methodically does the same thing over and over and over and over," added Bill McDonald, CEO of the Winnipeg Humane Society. "And it's really an indication that he's going slowly insane."

Not to mention that the physical conditions of the zoo in which he's trapped are far less than adequate. Arturo has no contact with other bears and has limited access to water pools.

Polar bears are built for an Arctic climate, where temperatures can plunge to -45 degrees Celsius (-50 degrees Fahrenheit). They are insulated by two layers of fur and a thick fat layer to help keep them warm. But in the scorching South American heat, it's no surprise that these features only exacerbate the problem.

"In fact, polar bears have more problems with overheating than they do from the cold," writes Polar Bear International.

Earlier this year, after word of Arturo's situation began to spread, campaigners around the world urged the Mendoza Zoo to transfer him to a more fitting facility in Canada's Assiniboine Park Conservancy. However, authorities informed the conservancy that an animal can only cross the border if it has three years' worth of medical records - records the Argentine zoo didn't keep.

Others assert that even if such records existed, Arturo is far too fragile to make the trip. Last February, vets in Mendoza concluded that he likely would not survive such a journey.

Still, animal lovers rooting for Arturo are not giving up, and pleas to have him transferred have only gotten stronger. Thousands on social media, including celebrities like Cher, have made their voices heard.

"Arturo is in distress," Laidlaw told the Mirror. "They say there's a risk if he is moved. But the risk is worth it."

Twitter activists have even presented a "Free Arturo" petition to Argentina's president, Cristina Fernandez de Kirchner.

Nearly 46,000 people have signed a petition on Change.org calling for Arturo to be moved.

Zoo visitors have taken videos of Arturo's psychosis, one of which can be viewed below.