INQUIRER: The Philadelphia Zoo’s Petal — at 52, the oldest African elephant in a U.S. zoo — died yesterday morning. The animal staff was unable to determine the cause of her death. It did not appear to be heat-related, and an initial exam revealed no health problems, said Andrew Baker, vice president for animal programs. Tests are being conducted and results are expected over the next few weeks. In the wild, African elephants typically live to their early or mid-40s, Baker said. Baker said the elephant-care staff found Petal lying on her right side in her stall when they arrived shortly before 7 a.m. They were instantly alarmed because she typically sleeps standing up. The zoo’s animal-care staff tried for nearly two hours to comfort her and to help her to her feet. Veterinarians were able to get a blood sample and analyze it, but it showed no indication of dehydration or major organ failure and gave them no other clues, Baker said. Her body temperature was normal — about 99.7 degrees — but she stopped breathing and died about 9:15 a.m. MORE