They are arboreal and prefer living in trees. Red-capped mangabey groups often venture to the ground and forage amongst the leaf litter on the forest floor.
Mangabeys are excellent jumpers.
Red-capped mangabeys have an extremely loud alarm call. They communicate with facial expressions, and chattering with their lips or open mouths. The westerly form of the red-capped mangabey is believed by some local farmers to be very destructive to their crops. They are large and slender, with a head and body length of 22 inches. The tail is longer at 28 inches.