This has been a question that I've spent a lot of time mulling over, trying to figure out where to draw the line based on how conscious/aware the animal is from a logical non-anthropomorphized point of view, a point of view that is not based on how intelligent or stupid I "feel" the animal is and not based on trying to draw conclusions from behavioral instincts that can be misinterpreted.

The closest I've got to that answer was finding this research paper I came across a number of years ago when researching fractional dimensions in mathematics after I quickly became of the opinion that fractional dimensions represent a possible potential evolutionary pathway for the development of consciousness after realizing a 1D curve can increase it's dimensional properties through repeated patterns (like how the Hilbert curve can make a 2D space), anywho, the paper explores the possible connection of this fractional mathematical dimensionality found in the fractal patterns of the EEG's of various species to the phenomenon of consciousness as a possible way of trying to look at the question of consciousness in a way that is quantifiable, and I think they may have very well been on the right track ... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1201004/#!po=64.7727

I really wish they analyzed the EEG's of more species in this fashion, because the paper leaves me with more questions than answers ... but I think my answer on where I would draw the line resides somewhere on that path of reasoning ... but more data and research is needed for me to come to an answer that doesn't resort to some form of anthropomorphized projection and misplaced empathy ... and misplaced empathy is something we humans do as a matter of basic nature, as demonstrated here.