The Adventures of Milo and Otis (1989)

Synopsis
Milo is a kitten, Otis is a dog. When Milo gets into a small box with the intention of taking a trip down a river, Otis follows. En route, the stars encounter bad weather, life-threatening situations, and even potential mates. Original made for Japanese TV under the title Koneko Monogatari, The Adventures of Milo and Otis contained some intense scenes that were edited out for Western audiences. For American consumption, the film was pared down to a G-rated 75 minutes, with a new comic narration added, written by Mark Saltzman and delivered by Dudley Moore. ~ Hal Erickson, All Movie Guide