Shanghai, March 29, 2012 (Xinhua) -- A staff member trains detective dog Jack at an internatinal mail distribution center in Shanghai, east China, March 29, 2012. The 10-year-old dog Jack has worked at the mail distribution center for more than 6 years, helping human workers to detect prohibited and restricted objects. In 2011, staff members in Shanghai detected the prohibited mails for 862 times, of which 288 times were detected with the help of Jack and other detective dogs. (Xinhua/Pei Xin)