The Cincinnati Zoo in Ohio has announced its plans to send the last Sumatran rhino in the United States to Indonesia so that he can mate and preserve his critically endangered species. There are an estimated 100 Sumatran rhinos left, and nearly all of them are in Indonesia. This is a roughly 90% population drop since the mid-80’s. Conservation experts at the zoo say the 8-year-old rhino, Harapan, could be on his way to Indonesia within a few weeks. His sister at the same zoo died from illness last year, and experts think her death may have been caused by a poor diet. Some experts think that the move is necessary because it is unsafe for Harapan to live in an unnatural environment.