I saw this as a kid in the 60s at a drive-in double feature with The Guns of Navarone. It's a live action movie featuring animals as all the characters. All I really remember is that it was about a group of friends, a dog, a rabbit, a duck and maybe another animal. A bad guy in a castle (played by a tarantula), kidnaps one of them and they go to rescue their friend. The ending has them escaping in a car down a road through a forest, and the bad guy tries to stop them by blowing up the forest. They drive off a cliff into a river (I think the car floated) and they get away. In all the years since, I've never seen anything remotely like this on TV or home video. Ring any bells for anybody?