ST. LOUIS – The Saint Louis Zoo is mourning the loss of one of its own, after the death of a beloved chimpanzee. Rosebud, nicknamed “Rosie” by zoo staff, was humanely euthanized on Friday after battling progressive arthritis that no longer responded to medication, the zoo said. The zoo said Rosie, who was about 55 years old, had other medical concerns often seen in elderly animals. “Rosie will be greatly missed by her chimpanzee family, caretakers and all who knew her,” the zoo said in a Facebook post. Rosie came to Saint Louis Zoo 17 years ago, in 2007, with her daughter Utamu. She was an essential part of the chimpanzee troop at the zoo, the post said. The care team at Jungle of the Apes, the indoor ape exhibit at Saint Louis Zoo, said Rosie was “simply the best.” “She would greet them by making endearing “raspberry” vocalizations, especially when they were delivering her favorite food – bananas,” the zoo’s post said.The zoo said Rosie’s favorite activity was lying in the sunshine in a nest she built herself.  In her time at the zoo, Rosie got to see her daughter give birth to her granddaughter, Raven, and helped Utamu in motherhood, the zoo said.