Doraemon is a cat-like robot that came from the 22nd century.
Logo Based on by Fujiko F.
It is because he tries to win Shizuka's favour and not to get harmed by Gian.
Apart from Doraemon, Ota had lent her voice to other iconic characters in Anime, including Leo in the 1966 Jungle Emperor Leo, Atsuko Kagami in the 1969 Himitsu no Akko-chan, and Baby Panda in Panda! However, the reason for the switch was never revealed.
Unlike Western works on science fiction, the manga did not explain the theory nor the applied technology behind these tools, but instead focusing on how the characters exploit their advantages, making it more children-friendly.
He used the same sequences of cartoons with regularity and continuity to enhance the reader's ease of understanding.