Some novels present a story form many points of view. Most movies tell only one person's side of the story. Sometime it's easy to use the strongest point of view, or find the character with the most dramatic experience. It depends on which themes the scriptwriter wants to explore.
Animals are just pure, uncomplicated entities of creation from God. They live like the Maasai do in Kenya-for each day is forever to them and the "Now" is what they live in. You can get aggravated with your pets and yell at them, but in a matter of minutes they are licking your hand again in love.