Red-flanked duikers are territorial and mainly solitary, with a single antelope or a pair occupying a small territory for a few months and then moving elsewhere. The territory is marked with secretions from their preorbital glands. The duikers are most active in the early morning and shortly before dusk. They move about while browsing and keep a sharp lookout for possible predators; if startled, they lower their heads and dive into the nearest dense area of vegetation. They are hunted by a number of predators including leopards ("Panthera pardus"), crowned eagles ("Stephanoaetus coronatus") and African rock pythons ("Python sebae") but are also hunted by man, who probably kills more duikers than the other predators combined.