A suburban zoo is trying to figure out why a young red panda died earlier this week.

The Elmwood Park Zoo said Clinger died Sunday and an animal autopsy, known as a necropsy, did not provide a conclusive cause of death.

"Clearly we here at the Zoo are stunned as Clinger showed no obvious signs of illness or distress," the zoo wrote on its Facebook page Friday.

The year-and-a-half-old red panda and his two brothers, Shredder and Slash, arrived at the Norristown zoo in June, a year after they were born at the Smithsonian Conservation Biology Institute.

The zoo said it was awaiting the results of tissue analysis being conducted by a zoological pathologist to learn more about Clinger's death.

Shredder and Slash received examinations this week that included blood work and x-rays, and both were found to be in good health, the zoo said.

Red pandas typically live about 10 to 12 years.