The Cowboys and Redskins have one of the oldest and most intense rivalries in the NFL. So much so, in fact, that it is affecting snack time in the animal kingdom.

One Redskins fan has conditioned her dog, Dexter — named for former Redskins defensive end Dexter Manley to refuse his favorite treats when they are associated with the rival Cowboys. As soon as the treat is once again associated with the Redskins, Dexter happily chows down on the duck jerky.

Robert Griffin III may be the future of the franchise, but diehard fans like Dexter are what make the Redskins worth playing for.

Check out Dexter’s fanhood in the video below.