The 1st link on the Google search I linked to was my source. http://www.bbc.com/news/science-environment-31001941

The Guardian article is written by someone who is most likely a freelance writer. Their goal is to pump out articles that make attention grabbing claims while staying truthful. The author was not a rhino expert and likely didn't do much journalism research to find the facts people need to know, but some sob story about the last of it's kind is better news (more shares, more likes, more viewers, more ad revenue).