“Quick, head downhill!” orders Mr D. We gaze at our trusty tour guide in bewilderment. For more than two hours we’ve been trudging uphill in search of gorillas and even though our porters have cleared a path for us with machetes, it’s been hard going. Tripping on vines, slipping on mud, nettle stings: why would we want to turn tail?

On the slope above us a gorilla suddenly lumbers into view, and we understand Mr D’s excitement. After spending much of the morning moving ever further away from us, the gorillas have had a change of heart. Now, they’re headed straight for us.