Yeah, but you know what people MEAN using the word sentience. It's not at all unusual for word usage and word definition to differ. If someone says, "animals lack Human sentience," you know what they're saying, or what they're trying to say. In any event, yes, there are a few animals - a very few - who can recognise themselves in a mirror. Amongst these, believe it or not, are a couple species of birds ... Eurasian magpies, amongst them. Whales pass on what could be arguably defined as their "culture." Elephants, famously, recognise the skeletons of their own as being dead elephants and seem to act very respectfully towards them. There are many examples throughout The Wild Kingdom.™ But even a magpie can't break free of instinct and fly to the Moon.
How Mankind broke through that barrier is a complete mystery to scientists, even now, and it's ourselves!!! It should be obvious how it happened, but we may never fully understand it. But as far as an Alien Species would go, I remain convinced that they would not look animalistic, as some have prophesied. I believe that once Human-level awareness is achieved, primitive features start becoming unattractive. They don't want to look like animals, even on a subconscious level and begin to breed away from that pattern to something more sleek and developed-looking. And if they have no qualms about using Genetic Engineering on their own, then the results are going to be even more distinct and different from the animal kingdom they're surrounded with.
