In this case,
a dog still has a humanoid body. Animals with a non-humanoid body would be something like a bivalve. (Dogs are also pack animals, so they can qualify for a 1+ PRS under the NG208 rules.) We know how to read the body language of a dog; we don't know how to read the body language of a tree.
For comparison, the example Horta statblock has a PRS of 4. This is a creature with an entire episode revolving around how hard it is for humans to communicate with it.
The creatures with PRS 0 in
Creatures tend to be arachnids, slugs, or solitary predators, although I think it is inconsistently applied across authors' sections, with eels having PRS 1 or 2 for a chunk and then things like vultures and sabre bears having PRS 0 later.
I'm mostly wondering what in the android-ness qualifies it to go below the minimum 1 for PCs in the PG.