Are humans freaks of nature?

The argument that animals on Earth currently have very little understanding of human behavior makes sense (although my dog proves that wrong, at least sometimes). And it is clear that there is a significant intelligence gap between humans and all other animals on our planet. So animals indeed may not be the greatest analog for technologically advanced extraterrestrial life forms. (This may only hold true in terms of smartness, however—the diversity of living things on our planet suggests many possibilities for other aspects of alien life, including anatomy, communication, and social behavior.)

There is a deeper underlying question here. Since we doubtlessly did originate from animal ancestors, the gap between us and them must have been bridged at some point in time. Perhaps it was not a jump, but a continuous evolution. Were the mental abilities of the cavewoman or caveman really as advanced as today’s humans? How much ability for abstraction and appreciation of complex numbers did they have?

Since modern humans are the evidence that bridging the gap is possible, we might ask why it wasn’t bridged earlier, perhaps by an intelligent octopus, a smart dinosaur, a dolphin, or another ape? They’ve had millions more years to evolve than we have, but in their case the gap was not overcome. Are we really so special? If so, what it is it, exactly, that makes us special? Being a natural-born cyborg, as Andy Clark argues?