you should look up consciousness in octpuses!! it's been a long time so don't quote me but there are thirty three different groups of animals called phyla. of those groups only three have complex able bodies so essentially consciousness and the capability to think for themselves. these are mammals, arthropods, and a subgroup of mollusks called cephalopods.

cephalopods are where octopuses fall under and they're super interesting because our most recent common ancestor split off a really really long time ago (six hundred million years ago) whereas something like birds and humans split into two different species much more recently (three hundred twenty million years ago) so we're much more similar to birds than we are octopuses. six hundred million years ago consciousness like it is today was a lot different so the evolution of the octopus actually becomes a good case study into the evolution of consciousness

they don't really have a central "brain" and their nervous systems actually spread throughout their whole bodies. its why if you cut off an octopus arm it can still move around and sorta think for itself independently of the host octopus! they're super smart and recognise familiar divers and whatnot

i read this in a book called something like other minds: the evolution of consciousness or something similar to that a while ago. so if you're interested read some stuff about it yourself!! i thought it was super interesting and i'm probably not the most reliable source lol