The other had the mental capacity of pine nut and loved everyone.
A theory of intelligence HAS to include non human animals, such as dogs and cats. But I wouldn't go as far as to assume they can "understand" symbolism in the level we do, which requires shared models of the world with multiple levels of abstraction. And this is coming from the guy who argues WE are also animals.
A lot of dogs that score low on these intelligence scales are not stupid but stubborn. Basenjis are an example: they know what they are there to do, and you're not going to tell them otherwise. Shih Tzus, on the other hand, may just be airheads.