Dublin Zoo has announced the death of one of its best-known animals.

45-year-old Bornean orangutan Sibu arrived at the zoo 40 years ago this year.

He spent seven years in Rhenen in the Netherlands, where he was loaned for a breeding programme, before returning in 2008.

Dublin Zoo’s 45-year-old Bornean orangutan Sibu. Image Dublin zoo

In a statement, the zoo said he had been showing symptoms consistent with an age-related cardiac and respiratory condition for the last number of weeks.

He died while veterinarians were carrying out an in-depth assessment to confirm that he was suffering from progressive cardiac disease.

Dublin Zoo’s 45-year-old Bornean orangutan Sibu. Image Dublin zoo

“Everyone in Dublin Zoo is devastated by the loss of Sibu, who has been an iconic figure at the Zoo since he first arrived 40 years ago this year,” the zoo said in a statement.

“He was gentle, caring and highly intelligent – forming strong bonds with the keepers who cared for him.

“His absence will be felt by the whole team, and undoubtedly by the millions of visitors who were fortunate enough to see him over the years.”

The zoo is awaiting the results of a post-mortem to confirm his cause of death.