I used to be so impressed by how many degrees of freedom (DoF) a spider has in total. like they have:

• eight legs (probably around 2-3 DoF each)
• pedipalps (3 DoF?)
• chelicerae (3 DoF?)
• very complex mouth parts (I don’t even want to guess lol)
• probably some DoF for their bodies too - like where their cephalothorax connects to their abdomen
• definitely some complex parts for their spinnerets

and I always wondered how their brains were able to handle all of that complexity - since my brain certainly couldn’t

but then I thought about it more and:

• 8 of my fingers have an equivalent DoF to a spider’s 8 legs
• let’s say that my thumbs have equivalent DoF to a spider’s pedipalps. that sounds about right to me
• now let’s say that my arms (not including my fingers - I already counted those) have equivalent DoF to a spider’s chelicerae. I actually suspect that my arms have more, but this is a conservative guess
• I also have very complex mouth parts, so we’ll call them equivalent
• my abdomen has plenty of DoF - probably more than a spider’s
• let’s say that their spinnerets are about as complex as my facial muscles. I don’t know much about spinneret anatomy but I have a lot of different muscle groups that I can control in my face, so this seems like a generous comparison to me

so I’ve already counted what I think is a roughly equivalent number of DoF, but I haven’t even included all of the DoF in my legs, feet, and toes (I think this is around 6, or maybe more)

so yeah I think that my body is equivalently complex to control to a spider’s body - if not moreso

obviously a spider’s brain is much smaller than mine, but it seems like brain size really doesn’t matter too much. it definitely doesn’t slow crows down. in fact I think that thought, creativity, etc. are such new “inventions” of evolution that it comes down more to optimization than raw neuron count, and I think that human brains are probably wildly, shockingly inefficient at doing what they do so well