Although chimpanzee rehabilitation is the primary focus of Chimfunshi, other animals benefit from the Siddles' care and attention as well. Antelopes, baboons, monkeys, tortoises, squirrels, bush babies, dogs and birds have all been nursed back to health at the orphanage, but the biggest resident of all is Billy the hippo.

Discovered in 1992 along the Kafue River at about 10 days old, Billy was rescued by game rangers who found her lying under her dead mother's body. The tiny calf had numerous wounds along its back and belly as a result of hunters’ spears, and required constant attention to survive the trauma. Unfortunately, the name "Billy" -- in honor of one of the hippo's rescuers -- was chosen before its sex was known.

Billy's size often intimidates visitors when they see her come plodding along in their direction, and the Siddles' pantry is clearly one of her favorite destinations. She was raised in the Siddles’ house alongside their dogs, and regarded the leather sofa as her private domain until it finally collapsed under her weight.

At present, Billy weighs over 1,500 pounds – yet still greedily accepts two bottles of milk per day.

Billy has grown up with chimpanzees and is familiar with their calls, their smell and their company. In fact, when a particular group of youngsters that she’d come to adopt had been moved to a larger enclosure without telling Billy, she became extremely agitated and upset. It was only once Billy discovered their new enclosure did she lay down in front of the wire mesh and sigh contentedly.