Uromastyx is a genus of African and Asian agamid lizards, the member species of which are commonly called spiny-tailed lizards, uromastyces, mastigures, or dabb lizards. Lizards in the genus Uromastyx are primarily herbivorous, but occasionally eat insects and other small animals, especially young lizards. They spend most of their waking hours basking in the sun, hiding in underground chambers at daytime, or when danger appears. They tend to establish themselves in hilly, rocky areas with good shelter and accessible vegetation.
Their size ranges from 25 cm (10 in) (U. macfadyeni) to 91 cm (36 in) or more (U. aegyptia). Hatchlings or neonates are usually no more than 7–10 cm (3–4 in) in length. Like many reptiles, these lizards’ colors change according to the temperature; during cool weather they appear dull and dark but the colors become lighter in warm weather, especially when basking; the darker pigmentation allows their skin to absorb sunlight more effectively.
Their spiked tail is muscular and heavy, and can be swung at an attacker with great velocity, usually accompanied by hissing and an open-mouthed display of (small) teeth. Uromastyxes generally sleep in their burrows with their tails closest to the opening, in order to thwart intruders.