Some books I have on extraterrestrial life. How and under what conditions it would evolve and what they would look like.
In a lot of these books they argue that unlike Sci fi movies and TV shows it would be unlikely that they would be humanoid.
It would seem to me that if we are talking about a somewhat earth like planet that nature usually repeats successful patterns. If a species is to be intelligent and tool making that being bipedal frees up the hands to make tools etc.
And then there are crabs - with multiple legs and appendages adapted as manipulators. Or octopi, with appendages in radial symmetry that are all useful as manipulative organs.
Life takes many, many forms, and nearly all of them are capable of adaptation to serve multiple purposes. Ever watched an elephant reach out with its trunk and pluck a single flower from a mass of them? I have.
Bipedality evolved out of quadrapedal ancestral forms, which evolved out of bilaterally symmetric 4 finned aquatic forms. It was not pre-destined, it is not preferable - it is simply that form which succeeded, for many reasons.
There's also a wide range of electrical pulses completely capable of "completing a task" with absolutly no need for any humanoid/mechanical structure.I could tell you that i've actually come across this particular species of alien life,but that's just crazy talk..instead i'll offer a hypothetical image of what one might look like.
Go into the bathroom and have yourself a looksee' in the mirror,now lean in and whisper this to yourself.."what are you"