This is so cool, look at how the head and body are a single stroke! Starts at the bottom of the head then ends at the top of the body - they must have done that to preserve ink or something?
Interesting how the tools we have access to affect the art we make.
Time of day is addressed in the study and
They also mention that the presence of the sun is possibly likely to affect dogs less than humans - meaning that dogs might have less aversion to facing the sun.
Study is here: https://frontiersinzoology.biomedcentral.com/articles/10.1186/1742-9994-10-80