If dogs have consciousness, then there is no line between dogs and humans.
If mice have consciousness, then there is no line between mice and dogs.
If bugs have consciousness, then there is no line between bugs and mice.
etc.
Until you get to, say, a rock rolling down a hill to find the low-energy spot, or an electron... Does that have consciousness? Most people would say no, but I would say then, where does "no line" become "line"?
This is a fairly solid proof of panpsychism imo.
edit:
You can go up the chain as well, from the complex (human beings) to the very-complex: groups of friends, to companies, which are collections of human beings, to the global economy, which is a collection of collections of human beings. I think that's as far up as it goes, but it is interesting to think about.