Sad news yesterday from the Smithsonian National Zoological Park. Rokan, the almost 20 year old Sumatran tiger (Panthera tigris sumatrae), was euthanized after several years of worsening health conditions. He was an amazing big cat who sired 10 cubs during his lifetime. He should be remembered and celebrated for the contributions he made to tiger conservation efforts. You can read more about the story at the Zoo's Tiger Diary.