Keepers at Whipsnade Zoo celebrated on Sunday as their oldest chimpanzee Koko reached her 50th birthday.Koko was treated to a birthday feast featuring her favourite foods, including gem lettuces and cherry tomatoes, before playing in the sunshine with younger chimps Phil, Grant and Elvis.Whipsnade Zoo primate keeper Grant Timberlake said Koko still has the energy of a young chimpanzee, despite outliving the average chimp by more than a decade."Koko might have just turned 50 but she's still in br

Keepers at Whipsnade Zoo celebrated on Sunday as their oldest chimpanzee Koko reached her 50th birthday.Koko was treated to a birthday feast featuring her favourite foods, including gem lettuces and cherry tomatoes, before playing in the sunshine with younger chimps Phil, Grant and Elvis.Whipsnade Zoo primate keeper Grant Timberlake said Koko still has the energy of a young chimpanzee, despite outliving the average chimp by more than a decade."Koko might have just turned 50 but she's still in brilliant health, thanks to the dedicated care of our zookeepers and veterinary team," said Mr Timberlake. "Particularly when she sees her favourite food, it's like she's 20 years young again - climbing and swinging as fast as she can through the trees to reach it."Koko was born at Dudley Zoo in 1973, and moved to London Zoo when she was nine. She moved to Whipsnade Zoo, the UK's largest, aged 33, and now now joins the zoo's "Golden Club" of other half-centenarians.The zoo's oldest animal, Gladys