Zoo authorities in the Indian capital, Delhi, have held a party to celebrate the 57th birthday of Rita the chimpanzee, its oldest resident.
The birthday girl received presents and a cake was cut in her honour as schoolchildren sang Happy Birthday.
India's oldest living chimpanzee was born in Amsterdam in 1960 and arrived at Delhi zoo as a four-year-old.
She's a "very friendly" ape and always behaves "like a lady", zoo director Renu Singh told the BBC.
"On her special day, we wish her a very long life and good health," she added.
The party was held a day early because Rita's birthday falls on Friday, a day when the zoo is closed. Her presents included a soft football and other toys, as well as a new blanket.
"I visited her in her enclosure and fed her some dry fruits and fruits. I gave her two bananas since she's specially fond of them," Ms Singh said, adding that "Rita was delighted with her new blanket."
Party time for Rita
BBC's Geeta Pandey at the Delhi zoo
About 50 schoolchildren, teachers and officials gathered outside the zoo to celebrate Rita's birthday. They marched through the walkways shouting, "One step towards Rita".
Outside the ape's enclosure is a garlanded cut-out, and a cake with her likeness carrying the message "Happy Birthday Rita".
Khyati Nautiyal, who shares her birthday with Rita, says: "I'm 10 years old today. I'm happy I share my special day with Rita. If I were to meet her, I'll wish her happy birthday, then I'll tell her that today is my birthday too, and then I'll tell her that I'll pray for her long life."
After the cake is cut, the schoolchildren have a little party - with cakes, muffins and samosa patties.
As Rita doesn't come out of her enclosure, we watch the "birthday girl" on a television screen happily accepting the food zoo officials hand her, oblivious to the fact that it's her special day.
According to an official biography of Rita, which was handed out to journalists at the birthday bash, she was born at Amsterdam zoo on 15 December 1960 and was brought to Delhi on 27 February 1964 in exchange for domestic cranes.
She was paired with Max, a male chimpanzee brought from London zoo. Together, they had four children but none survive.
From 1985 to 2006, she was loaned to a zoo in Punjab for a breeding programme, but she didn't have any success there.
Chimps only live up to about 40 years in the wild, but have a much longer life expectancy in captivity.