The Namaqua chameleon (Chamaeleo namaquensis) is a ground-living lizard found in the western desert regions of Namibia, South Africa and southern Angola. General anatomy Chamaeleo namaquensis is one of the largest chameleon species in southern Africa, and reaches up to 25 cm in length. Females are larger than males, though the latter are proportionately more robust and have larger heads and head ornamentation, as well as a bulge under the tail base due to the presence of hemipenes. Its tail is far shorter than its body and those of other arboreal chameleons as an adaptation to its primarily terrestrial habitat. It has large dorsal spines and a prominent, pointed casque on the back of its head and lacks the neck flap of other Chamaeleo species. Like many chameleons, this species has nasal salt glands which excretes excess minerals such as sodium chloride and potassium. It has hygroscopic skin, and shares a feature with some other lizards (such as the thorny devil, Texas horned lizard, Saara hardwickii, and the giant girdled lizard) in that it can drink moisture in contact with its scales through capillary action. Thermoregulation Although capable of changing colour, this chameleon is usually some shade of grey or brown with several lighter patches on the flank, dark patches below the dorsal ridge and yellow or red striping on the throat. This ability aids in thermoregulation, becoming black in the cooler morning to absorb heat more efficiently, then a lighter grey color to reflect light during the heat of the day — or showing both colors at the same time, neatly separated left from right by the spine. Like most desert animals, it is adapted to high environmental temperatures, but can also tolerate periods of low temperatures. Although temperature varies throughout the year, the natural habitat of this species has a yearly average coastal temperature of 19.3 °C in the air, and 26.6-31.8 °C on the substrate surface. Further inland, air temperature averages at 24.1 °C while substrate temperatures average between 30-34.5 °C. Distribution This chameleon species occurs naturally throughout the arid western part of southern Africa, and is particularly common in the Namib Desert. It is recorded as far south as Sutherland, in the Western Cape, South Africa, and as far north as southern Angola. In the furthest eastern edge of its range, in eastern Namibia, it overlaps with the natural range of its relative, the flap-necked chameleon.