The number of wild mountain gorillas, who are at risk from humans, is increasing for the first time in years. This is thanks to the efforts of conservationists like Uganda's first-ever wildlife veterinarian, Gladys Kalema-Zikusoka, who says they are truly gentle giants. There are just over a thousand mountain gorillas left, mostly high in the mountains in Uganda, Rwanda and the Democratic Republic of Congo. Kalema-Zikusoka has also written a book, "Walking with Gorillas", charting her life from young enthusiast to wildlife campaigner.