Icon of the Runaway spacecraft

The sapient aliens lined up in order from shortest to tallest: scuds, who are a parrot-like crustacean; avians, a bird-like alien with large bat ears who walk on their wings; bug ferrets, a whiskery hexapod with a tube-shaped body; humans, an upright biped with mostly hairless skin; and centaurs, large tiger-striped hexapods with hooved toes and a short trunk.
The Sapient Aliens:

Sapient life evolved five times naturally in the Milky Way Galaxy, and once was created on accident. Although each of the depicted aliens have many names for themselves in many languages, these articles use the most common Jovian English terms.