Little Dog is a small orange Dachshund. Little Dog is much more energetic and hyperactive than Big Dog.
Little dog
Little Dog is completely scared by cats (possibly a case of ailurophobia), and when a cat appeared, it was Big Dog that had to scare the cat away. He does know a little about history (such as when in "Substitute Teacher", an Abraham Lincoln parody was played, when the Lincoln actor (Mr. Hollywood) dies from a sword strike, the little dog remarks "I thought Lincoln was shot"). He often refers to things he doesn't like as "caca!" In one episode, Sheep Dog, it was revealed he didn't know his own name. When he asked Big Dog about it and got "I don't know" as reply, he wrote "Ida Know" on the form.