Abstract
The spiny-tailed lizard Uromastyx aegyptius and the black scorpion Androctonus crassicauda are frequently found together in nature. This relationship has been studied under laboratory conditions. No interactions were observed between the diurnal lizard and the nocturnal scorpion either during the day or the night. These animals are mutually tolerant, and immunological studies confirmed that the scorpion never stings the lizard. The lizard furnishes shelter for the scorpion in a location full of cohabiting prey and the scorpion provides protection for the lizard by stinging its enemies.