What intelligent life in the universe probably looks like

There are several requirements and constraints that intelligent life is probably subject to.

Let’s assume that they would share the basic characteristics of carbon-based life on Earth, which is a fairly realistic assumption considering the similar problems that convergent evolution solves in a similar way.

So they too would have eyes, a mouth, an anus, bilateral symmetry, encephalisation, etc.

Civilizations are more likely to be found on the surface of a planet rather than in water, because aquatic sentient life forms would have problems discovering fire and all its uses, such as metallurgy, and there is also less usable solar energy in water.

This gives a disadvantage to sentient creatures on ocean planets that are in the habitable zones of their solar systems.

On land, nature has to make a compromise in the body plans of larger organisms, between a greater number of limbs resulting in more stability but less energy efficiency, and vice versa, between a few limbs that have little ‘consumption’ but that are also very unstable. The trade-off between efficiency and stability means that large organisms tend to have as fewer limbs as possible (a spider has eight, a diplodocus four).

This means that hypothetical sentient creatures, in all likelihood, would walk on two or at most, on planets with low gravity, four legs.