Southern Tree Agama (Acanthocercus atricollis) M

Family Agamidae 

These lizards have quite a range of colours and are able to change them like a chameleon.

They are our largest Agama species and in the breeding season, the males head becomes bright blue.

Also see: http://saphotographs.blogspot.com/2011/10/southern-tree-agama-acanthocercus.html