The blue duiker is a small antelope; in fact, it is the smallest duiker. The head-and-body length is typically between 55 and 90 centimetres (22 and 35 in). It reaches 32–41 centimetres (13–16 in) at the shoulder and weighs nearly 3.5–9 kilograms (7.7–19.8 lb). P. m. anchietae is the largest subspecies. Sexually dimorphic, the females are slightly larger than the males. The blue duiker is characterised by a flat forehead, large eyes, small ears with a line of white, large nostrils, a broad mouth and agile lips. The dark tail measures slightly above 10 centimetres (3.9 in).
A remarkable feature of the tail is the row of white crinkly hairs on either flank that reflect light efficiently, so that when the animal moves its tail up and down, it looks like a luminous signal in the dark habitat. The duiker has short, spiky horns, around 5 centimetres (2.0 in) long and hidden in hair tufts. A row of minute pores surrounded by a few hairs in the preorbital glands (near the eyes) secrete an opaque liquid consisting of 45 volatile compounds. The pedal glands (near the hooves) produce a pungent, whitish fluid.
Ecology and behaviour
The blue duiker is diurnal (active during the day). Secretive and cautious, it confines itself to the forest fringes. Territorial, individuals of opposite sexes form pairs and occupy territories, nearly 0.4–0.8 hectares (0.0015–0.0031 sq mi) large and marked by preorbital gland secretions. The animal rubs the preorbital glands on trees and logs to mark its territory with the fluid produced by the glands.
A vocal bovid, bird-like chirps denote curiosity in the animal. It can let out yowls typical of cats if distressed. A female not in oestrus will avoid the male’s advances, and may even let out a whistling call.
