The oldest resident of Edinburgh Zoo has died at the age of 50.
Ricky the chimpanzee had been losing weight and looking "out of sorts" before it was realised he had a badly diseased heart.
His keepers at the zoo paid tribute to Ricky, who arrived at Edinburgh Zoo on April 20 1966 and died on Monday.
Dee Masters, Budongo Trail team leader, said: "Ricky was one of the most loved animals at Edinburgh Zoo and a really important member of our chimpanzee group in Budongo Trail.
"All the primate keepers here at Edinburgh Zoo had a soft spot for Ricky and, most importantly, he was an integral member of our chimpanzee group. He had so much character and was one of the most caring and peaceful of our chimpanzees.
"Ricky was never a dominant male and never showed much interest in chimp politics or hierarchy. He was much happier relaxing and playing with youngsters in the group."
Other chimpanzees in the group were said to have sensed that something was wrong with Ricky because they began to respond differently to him. The zoo's veterinary team carried out an X-ray which showed his heart was in poor condition.
Simon Girling, head of veterinary services at Edinburgh Zoo, said: "Ricky's keepers advised that he was generally quite out of sorts and needed further exploration. We anaesthetised him and carried out a number of routine tests, where an X-ray revealed that his heart was in a very bad state.
"We felt that Ricky had around only two weeks left at best but, as it turned out, he passed away later the same afternoon."
Ms Masters added: "Ricky was old for a chimpanzee and was extremely lucky to reach the grand age of 50. But I speak on behalf of all his keepers here in Budongo Trail in saying that we will miss him dearly."