Rugrats - Season 6 - Eps 15: Pedal Pusher
Stu, Chazz & Howard take the Rugrats to the zoo, where the employees wear animal costumes. After noticing this, the Rugrats learn that animals are people, too, as they see these ""animals"" do human stuff like eat ice cream, play with toys and sell souvenirs. When placed in a caged petting zoo, they think that they will turn into animals and remain there forever and ever. Later, when Tommy dropped his trusty screwdriver outside the pen, the Rugrats call on Dil and the real animals to help him out.
About Rugrats

Title: Rugrats
First Air Date: 1991-08-11
Last Air Date: 2004-08-01
Status: Ended
Rating: 7.603/10 (from 715 votes)
Language: EN
Seasons: 10
Total Episodes: 322
Network: Nickelodeon
Genres: Family, Animation, Kids, Comedy
Production Companies: Klasky-Csupo, Nickelodeon Productions, Nickelodeon Animation Studio
Synopsis
Focuses on a group of toddlers, most prominently Tommy, Chuckie, Phil, Lil, and Angelica, and their day-to-day lives, usually involving common life experiences that become adventures in the babies' imaginations. Adults in the series are almost always unaware of what the children are up to; however, this only provides more room for the babies to explore and discover their surroundings.
Cast

E. G. Daily
Tommy Pickles (voice)

Kath Soucie
Phil DeVille / Lil DeVille (voice)

Cheryl Chase
Angelica Pickles (voice)

Dionne Quan
Kimi Finster (voice)

Tara Strong
Dil Pickles (voice)

Joe Alaskey
Grandpa Lou Pickles (voice)

Melanie Chartoff
Didi Pickles (voice)

Tress MacNeille
Charlotte Pickles (voice)

Jack Riley
Stu Pickles (voice)

Cree Summer
Susie Carmichael (voice)