MIAMI, Fla. (WFLA) — Zoo Miami’s patriarch Sumatran tiger, Berani, was euthanized Thursday after receiving a “heartbreaking” diagnosis.

Zookeepers brought the 15-year-old big cat to the zoo’s animal hospital on Tuesday after several days of low appetite and lethargy, according to a news release from Zoo Miami.

Veterinarians found Berani was severely dehydrated and anemic, which prompted more testing. They found he had an enlarged spleen and abnormalities of the kidneys.

On Thursday, test results revealed Berani developed cancer of the spleen.

“Sadly, due to his advanced age and an extremely poor prognosis for any improvement, the very difficult decision was made to humanely euthanize him to provide him the dignity in death that he displayed throughout his life,” Zoo Miami wrote in a statement.

Berani’s legacy lives on through his two cubs, Satu and Ndari, who were born at Zoo Miami. A zoo spokesperson said they plan to announce “something much more uplifting that will only add to this magnificent cat’s legacy.”

There are less than 500 of the critically endangered Sumatran tigers left in the wild, according to Zoo Miami. In their native habitat, the Indonesian island of Sumatra, they are threatened by poaching and loss of forest from palm oil plantations.