"When you have good control, it limits the risk to human health," he says. (See pictures of orphan gorillas rescued from poachers.) All the while they keep a trained eye on the gorillas.

What would you do if you were approached by a silverback mountain gorilla? Watch the amazing footage of this close encounter.

An outstanding student helper, he shared my aim to balance research with the goal of saving the imperiled mountain gorillas that I was studying from my base camp in the Virunga Mountains of Rwanda ...