Octopuses are a member of the Cephalopod Class of animals which also include squids, cuttlefish and nautili.

Cephalopods diverged from other animal life around 500 million years ago. The nautilus is one of the oldest animal species still existing, and amazingly enough, it still looks very much like it did 500 million years ago.

Octopuses are a little younger, having existed for a mere 300 million years or so! Being soft bodied, as you can imagine fossils are rare. The earliest fossil dates from around 298 million years ago.That fossil has eight legs, but the modern octopus has evolved considerably since then.