WASHINGTON (WUSA) -- National Zoo officials say a 20-year-old Andean (or spectacled) bear was euthanized on Monday after his health declined rapidly in the last three weeks.
Nikki developed an ulcer on his lower jaw in 2011 which was later found to be "aggressive squamous cell carcinoma, a type of cancer", say zoo officials. He then underwent had the affected section of his jaw removed and was placed on oral chemotherapy to slow any potential regrowth of the tumor after a veterinary oncologist consultation.
Zoo officials say the carcinoma still spread to other areas of his body.
Nikki was severely overweight when he arrived at the zoo five years ago and was put on a new weight-loss plan. He lost almost 200 pounds in a year and was able to sire two cubs in January 2010. Bernardo and Chaska were the first of their species born at the National Zoo in 22 years.