WMG / Oobi

Oobi, Uma, Kako, and Grampu all have lookalike relatives that work for the circus.

In the episode "Pretend Circus!", if you look very carefully at the circus poster in Oobi and Uma's bedroom, you can notice that the circus performers have striking resemblences to Oobi, Uma, (the acrobats) Kako, (the ringmaster) and Grampu (the clown). It's most likely suggested that the performers are not really the main four characters of the cast, so it's more likely that they all have identical relatives of theirs that work for the circus (as the heading says).