I think it should also be considered that if we have consciousness then it has to evolve at some point. And if it something complex, and in this case I'm sure it is, then it's going to takes millions of years minimum to evolve. Unless someone think consciousness developed when humans, neanderthals and our other relatives evolved from whatever relatively recent ancestor, then where consciousness began is going to have to be pushed back. The further it's pushed back the more animals there are with consciousness.

Ultimately it's up to the brain and our brains aren't that different from other animals.