A cow? A rat? A spider? An ant? A plant? A bacterium?
I'm always skeptical of someone who says they don't draw lines. Usually, the "no lines" logic becomes absurd at some point. Sure, drawing lines is a difficult thing to do sometimes, but a line has to go somewhere.
Personally, for some circumstances I think it's perfectly fine to draw the line at human/not human. For other circumstances I would draw it at intelligent/not intelligent (a much harder line to define). For others, I would say has a brain/does not have a brain. No need to have one line.