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The dwarf antelopes in the genus Madoqua are known as dikdiks. Groves (2011) recognizes 12 Madoqua species, nearly all of which are confined to the Horn of Africa (M. damarensis is found in southwestern Africa). Most of these species were formerly considered subspecies of M. saltiana or M. kirkii (the other two traditionally recognized species are M. piacentinii and M. guentheri, the latter of which Groves states includes two strongly distinct subspecies that might better be treated as species). The former subspecies of M. saltiana are M. phillipsi, M. hararensis, M. swaynei, and M. lawrancei; the former subspecies of M. kirkii are M. hindei, M. cavendishi, and M. damarensis. Madoqua thomasi was formerly treated as a synonym of M. kirkii.
Dikdiks are very small antelopes with long legs and a fine soft coat. They have relatively large eyes and ears, a prominent crest, and a fur-covered nose that is enlarged into a proboscis in some species and functions as part of a cooling system (dikdik species without this well developed system may stay cool by being mainly nocturnal). The tail is vestigial, but the pale underfur can be fanned to create a striking visual signal. These are arid-adapted antelopes and Kingdon (1997) notes that the two arid regions in which they occur (Horn of Africa and southwestern Africa) have often been connected by an arid corridor in the past.
All dikdiks rely on low thickets and succulents growing on well-drained soils with little grass. If dense, tall grass becomes established, the dikdiks move away. Males scent-mark their territories, but their territories are determined largely by the movements the females. Territories are around a third of a hectare and population densities range from around 5 to 20 per square km. Many disturbances may elicit a discreet crouching or creeping departure, but a sudden flight tends to elicit breathy whistles from both partners in a territory, sometimes in a duet. When a pair reunites there is often face-rubbing in which the female may lick the male's preorbital glands, which secrete in response to excitement. Flight is generally brief but swift (speeds of up to 42 kph have been recorded).
The flexible well developed proboscis in some dikdik species is lined with numerous blood vessels in the mucus membrane. These are cooled by increasing the normal breathing rate from one to nearly eight breaths per second. The cooled blood returns to the heart via a sinus where hot blood going to the brain is cooled by this returning blood in a form of rete mirabile. Selective cooling via this countercurrent exchange mechanism minimizes the risk to brain function as general body temperature rises.