This rather sociable agama is normally found in small groups or colonies. It grows up to about 25 cm and has a thin dorsal crest that runs the length of its body. It typically has a short, plump body and a thin tail, with a triangular head. During the breeding season, the heads of the males become bright blue. The males also take to sitting on top of prominent rocks and are therefore a common sight in mountainous areas of South Africa. The females and young are a more uniform greyish-brown and are much shyer. It has some ability to change colour, although not to the same extent as chameleons, of which it is a sister group. When a male agama in breeding colouration is approached by a potential predator, it will lie flat against a rock and lose the intense breeding colours in favour of more cryptic colouration. A dominant male usually occupies a high point in the area and performs a pushup display and head nodding to warn off intruders.
Info source: en.wikipedia.org/wiki/Agama_atra
The photo was taken during August 2015 at Pine Lake Resort, Witrivier, Mpumalanga, South Africa.