A squirrel inspired Atsuko Nishida’s original design for Pikachu.
Nishida said she based the design on a squirrel because she was fascinated by the animal’s movements. The idea also influenced Pikachu’s cheek pouches: squirrels store food in their cheeks, while Pikachu stores electricity there. The final creature was later classified in the games as a Mouse Pokémon.
This distinction creates a common mix-up. Pikachu is officially associated with mice in its species classification and name localization, but its original visual inspiration came from squirrels. Its tail, pointed ears, rounded body, and red cheeks were adapted into a character that could be instantly recognized on the Game Boy screen.
Ken Sugimori finalized the design, and the anime later refined Pikachu’s proportions into a slimmer appearance that became familiar worldwide. The original games showed a rounder version, often called “Fat Pikachu” by fans, while later artwork and animation standardized the character’s look.