Throughout Family Guy, Brian is shown to be a personified and intelligent dog who has accomplished things such as writing a book and a play. However his is still at heart a dog. And dogs do things that humans don't.
Brian has been shown repeatedly on the show to have dog instincts:
- chasing the mailman/squirrel
- hating being in a car with the windows up
- occasionally finding/burying balls
This question was inspired by the second point when Brian is stuck in the car and the windows are closed. He then frantically tries to get out and says
I can't get out! Someone help me! I'm going to pee in here!
which suggests he is acting like an ordinary dog. It seems as though this only happens when the situation is humorous.
So why is Brian both dog and human? Surely he is smart enough to control the dog instincts. So why is he unable to stop himself doing things like this? Has Seth MacFarlane ever explained this?