the predominant theory is that the length of an organism's lifespan is inverse to the rate of it's metabolism. Look into Kleiber's law. Also worth reading the book Scale by Geoffrey West.
I'm reading this book "The Origin of Consciousness in the Breakdown of the Bicameral Mind" and it's quite fascinating to think deeply about what is Consciousness. I think the book does a good job of defining and explaining Consciousness.
Highly recommend it to think critically about the subject, but I think your point is valid, consciousness occurs for many things, and then it doesn't have to many other things. You don't need consciousness to nearly instantly detect that b comes after a sequence of {a,b,a,b,a,?}. You need consciousness to think about _why_ b comes after though. When you go for a swim and then recall the event, you most likely recall it in an objective or third person way mentally - the image or visual in your memory is that third person view.. but that's not actually how you experienced it.
I wonder how much of that applies to animals, and I wonder if we can ever get that answer.