Research Assistant

The film

Before the Seavers leave for a family vacation to San Francisco, they drop off their pets -- Chance, an adventurous American bulldog; Shadow, a wise golden retriever; and Sassy, a cautious cat -- at a friend's ranch. But when the animals start to worry that they've been left for good, the three embark together on a treacherous and thrilling journey to find their way back home through the California wilderness.

Synopsis from TMDB.