A dik-dik is the name for any of four species of small antelope in the genus Madoqua that live in the bushlands of eastern and southern Africa. Dik-diks stand about at the shoulder, are long, weigh and can live for up to 10 years. Dik-diks are named for the alarm calls of the females. In addition to the females' alarm call, both the male and female make a shrill, whistling sound. These calls may alert other animals to predators. Name The name dik-dik comes from an onomatopoeia of the repetitive dik sound female dik-diks whistle through their long, tubular snouts when they feel threatened. Physical characteristics Female dik-diks are somewhat larger than males. The males have horns, which are small (about ), slanted backwards and longitudinally grooved. The hair on the crown forms an upright tuft that sometimes partially conceals the short, ribbed horns of the male. The upper body is gray-brown, while the lower parts of the body, including the legs, belly, crest, and flanks, are tan. A bare black spot below the inside corner of each eye contains a preorbital gland that produces a dark, sticky secretion. Dik-diks insert grass stems and twigs into the gland to scent-mark their territories. Perhaps to prevent overheating, dik-diks (especially Guenther's dik-diks) have elongated snouts with bellows-like muscles through which blood is pumped. Airflow and subsequent evaporation cools this blood before it is recirculated to the body. However, this panting is only implemented in extreme conditions; dik-diks can tolerate air temperatures of up to . Adaptations for desert environments Dik-diks have special physiological adaptations to help them survive in arid environments. For instance, dik-diks have a lower density of sweat glands compared to other animals such as cattle. Similarly, in more arid environments, dik-diks can concentrate their urine. These adaptations help dik-diks preserve body water. Because of their small body size, dik-diks are predicted to have among the highest metabolic rates and highest energy requirement per kilogram of all ruminants. However, dik-diks have a lower metabolic rate than would be predicted for their size as a physiological adaptation to heat and aridity. Habitat Dik-diks live in shrublands and savannas of eastern Africa. Dik-diks seek habitats with a plentiful supply of edible plants such as shrubs. Dik-diks may live in places as varied as dense forest or open plain, but they require good cover and not too much tall grass. They usually live