Rocco, Polo's son, is a very annoying bratty baby chinchilla, but he sometimes has a sweet side...toward his parents, anyway. Stranger danger.
Considering Rocco cannot exist in his dad's world, he is not in any way canon to his story (or world. Sad, I know)

Distinctive Feature(s): He's smaller and chubbier, since he's a baby.

http://www.solosterminal.pichusworld.net/rocco.shtml