I always like these types of shots - and playing with the crop to figure out the best place for negative space is always a fun part of the challenge.
I generally find when working with small critters that because I'm so close to the subject, I have try for a greater depth of field - which means generally artificial lighting (unless I happen to be outside on a really bright sunny day). Little critters are also often moving which means a faster shutter speed is often better for sharpness. I do have an external flash that I can bounce off surfaces or even remove from the camera and remote control to get the lighting that works best.