I learned of the symbiotic relationship between the blue duiker and the vervet monkeys in June. The blue duiker use the monkeys as a source of predator protection and as the monkeys feed, they drop fruit to the forest floor, which the blue duikers quickly vacuum up.
While sitting in a blue duiker blind, I could hear the rustle of the monkeys feeding towards our location. My PH said that the duikers should be with the monkeys. Sure enough, after about 30 mins the first monkey appeared. A short while later a young blue duiker came into the opening and drank at the water hole. As the duiker was milling around, one of the monkeys saw us and thought we were a bit suspicious, gave a quick bark and took off. The duiker didn't hesitate a bit and was off in a flash right behind the monkey. My PH later said he could see two others further back in the bush, but I couldn't see them from my sitting position in the blind.