Argentina's last captive polar bear will remain in the country despite a petition by more than a half million people asking that it be moved to Canada. The director of the Mendoza Zoo in western Argentina said on Tuesday that the 28-year-old bear is too old to safely be relocated. Animal rights advocates say the bear, named Arturo, paces nervously in his concrete enclosure, and they suggest the animal suffers from depression. They have campaigned to move the bear to a zoo in Winnipeg, Manitoba, which has welcomed the idea. Even Newt Gingrich, the former US House speaker, has rallied to the cause. "If you love animals the way I do, please sign the petition to help the Argentinian polar bear, Arturo," he recently wrote on his Facebook page. "His current living situation is very sad, and he deserves to be saved," Gingrich wrote. The petition on Change.org asking Argentine President Cristina Fernandez to allow Arturo to be relocated had been signed by more than 500,000 supporters as of Tuesday. But zoo director Gustavo Pronotto said Arturo suffered only the typical ailments of old age, which would make relocation too risky because he would have to be sedated to travel.