Kabatotto
English name: Hippo and Thomas
Genres: Comedy
Type: TV, Episodes: 300
Aired: Jan 1, 1971 to Sep 30, 1972
Studio: Tatsunoko Production
Source: Unknown
Rating: G - All Ages
Synopsis:
Thomas is a cunning bird who sponges on Hyppo, the good-natured hippopotamus. Although Thomas is a dependent, living in Hyppo's big mouth, he always acts lordly and tries to outsmart his simpleminded host. However, their basic friendship and cooperation endures despite their frequent quarrels. The two play a prime role in this comic series, short yet full of originality. 

(Source: Tatsunoko website)