Dust Devils Dancing on Dunes
Dust devils make dark, diffuse scribble markings on the surface by kicking up dust, and are especially active in the summertime over dark surfaces, such as those with many deposits of sand-sized material.
The surface warms up in the sunlight, creating the right conditions to form dust devils. Mars also has larger dust storms that can deposit a thin layer of dust and eliminate the dust devil tracks.
This image shows a small portion of the sand dunes in Russell Crater, which are of special interest due to the peculiar channels that formed on the steep slopes.