The female Southern Agama (Acanthocercus atricollis) is quite indistinctive and blends in so well with the bark of a tree that unless she moves, she is not easily noticed.
For more information and pictures of the male, please click on the link.Like so many of our species, the patterns, colors and even protrusions on the skin add to their camoflage.
This lizard must be about 10-12 inches in length and are very shy so not easy to photograph up close.
With nails like that, they easily climb almost smooth surfaces. A feat which would be impossible for us.
During the breeding season, the males head is a much brighter blue than this as can be seen in the linked post.
Once again I apologise for some of the pictures being the wrong way around but it seems that Blogger has no intention of fixing the problem or allowing some method of correcting it.