What Is an R4 Card? Not a Nintendogs Feature

There is no "R4" in Nintendogs. You might be confusing it with:

• R4 Card: A flashcart for Nintendo DS that plays ROMs (game backups). It's not specific to Nintendogs and works with many games.
• Dog Breed: No breed in Nintendogs is called "R4."

If you clarify your goal, I can help further:

• Playing a specific game on your DS?
• Finding a specific dog breed in Nintendogs?
• Information about modding Nintendogs?