In this photograph provided by Smithsonian Institution, National Zoo Veterinarian Carlos Sanchez, right, used an eye scope to examine a Sumatra tiger cub held by Animal Keeper Jeanne Minor Thursday July 6, 2006 in Washington. Three tiger cubs, one male and two females were born at the National Zoo May 24, 2006. The 6-week-old cubs recieved their first round of vaccinations during Thursdays medicine exam.(AP Photo, National Zoo, Jessie Cohne)