Scientists (and philosophers) do not have an objective, universally accepted test for sentience (roughly "self-awareness") that characterizes the human conscious mind, so my answer is: nobody can prove one way or the other. Certainly many animal lovers will insist they do. Others will just as certainly insist they do not. I think it is safe to say that the lower animals do not. Creatures less sophisticated than jellyfish (for example) essentially have no real brain and no discernable "thought" processes. More advanced species exhibit problem-solving and advanced learning behaviors, but that can not be proved to reflect consciousness as we can program computers to "solve" and "learn" similar things. It is clear that the more advanced mammals have very complex behavior patterns and some appear to have human-like emotional responses, but, by most analyses, this is insufficient to conclude "consciousness" (of the same type as humans) with certainty.

(I assume that you mean whether animals have a self awareness, not whether animals feel guilty) That's a tough question. How do you know other humans have a consciousness? You only know that you are conscious. You deduce from that fact that other humans are conscious, too. You can't know that. You can't measure consciousness. It's possible that somebody could build a robot who would act completely human, show emotion, be able to learn and exhibit logical thinking. Still, such a robot would not be aware of himself. Animals, though, aren't robots. If you accept that all (or at least most, since some humans seem to not be conscious - if they're in a comma, for example, or if they're severely mentally handicapped) humans have consciousness, it should follow that some animals have similar if less well developed properties. Dogs clearly show emotion. They can be happy, sad, even feel guilty if they've done something wrong. Cats show similar emotions. Sometimes they're angry, sometimes they're comfortable. Some animals, like elephants, even mourn if relatives or "friends" die. They seem to be consciously aware of themselves and of others. They seem to know and recognize each other consciously. Other animals do not seem to exhibit any kind of consciousness. Ants seem to work like robots. They react to input in a logical manner, they don't value their own lives and they don't seem to be aware of what they're doing. So, to answer your question: Do animals have consciousness in the same way humans do? No, but at least some animals seem to be aware of themselves very similarly to how humans are aware of themselves.

Yes. It's not the consciousness that's different. It's what the consciousness is conscious of.

Possibly some do. I do know my doxie experiences jealousy, affection, happiness, anger and resignation. She also makes mental plans followed by actions to circumvent or create situations accordingly. I don't know if she thinks she's my dog or that I am her human. Either way, we are a good team at making each other's life good.

I have ofter pondered that very thought with regard to my pet doxie....just what is she thinking, what form does that thinking take, does she think in dog words and is she thinking all the time or just existing??

As always, it depends on what you define consciousness as being. Since there is no clear definition of this word, we can only speculate about the mysteries of consciousness regarding other humans, and animals. Studies have shown that animals have complex thought patterns, can learn complex behaviors and communication methods such as sign language, and they also cycle through the same stages of sleep that humans do. Animals clearly feel physical pain, although whether they experience emotional pain is debatable, it seems that they are capable of guilt, and it seems that their moods change. I don't deny that there is something 'it is like to be' an animal, and so yes, I do believe animals have consciousness, but I do not think it is the same as ours. Human brains are much more complex (thanks to evolution and our complex language system with syntax & semantics,) and we have many more interactions with our world (through technology) which have direct effects on our consciousness, so it would be silly to say that animal consciousness is the same as ours. However, if you define consciousness as simple self-awareness, the answer changes altogether and varies species to species. While some primate species can identify a paint spot on their faces using a mirror, other animals such as cats may not have the capacity or concept of oneself to show the same behavior.