Data Die
After loading Nintendogs, on the screen where the Nintendo logo is on top and copyright information on the bottom, press and hold L + R + A + B + X + Y simultaneously to delete your data from the cartridge.

Unlock: German Shepherd
Get 17000 Owner Points.

Unlock Jack Russel Terrier
While on a walk, your dog may find an Item called the Jack Russel Book. At this point you can visit the kennel buy a Jack Russel Terrier.

Unlock Pinscher
Collect 14000 Owner Points.

Unlock Schnauzer
Get 10000 Owner Points.

Unlock Toy Poodle
Get 25000 Owner Points.

Unlock Welsh Corgi
Collect 2000 Owner Points

Unlock Shetland Sheepdog
Get 8000 Owner Points.

Unlock Pug
Get 4000 Owner Points.

Unlock Japanese Style House (from Shiba Pack)
Get 20000 Owner Points.

Unlockable List -- U.S. Version
Dalmation: Get the "Fireman Hat" item.
Golden Retriever: Get 10000 Owner Points
Miniature Schnauzer: Get 14000 Owner Points
Pinscher Collect: Get 2000 Owner Points
Siberian Husky: Get 4000 Owner Points
Toy Poodle: Get 8000 Owner Points

Unlockable: Rooms
Desktop: Get 6000 Owner Points
Seaside: Get 12000 Owner Points

Unlock Outer Space House
Accrue 18000 trainer points to unlock the outer space house.

Hint: Free Gifts and Toys
While you can purchase new toys for your pup to play with, you can actually get some goodies for free if you know where to look. When you take your Nintendog on a walk, outline a path that goes by the blue "?" boxes marked on the map. Your puppy is likely to run off screen at those points and come back with a present for you!

Your puppy will also randomly run to get presents for you if you leave the game on the "Home" screen for long. If left unattended, your Nintendog will leave the apartment and stay off screen. Simply tap on the center button (the circular one) to whistle and call back your pup who should be carrying a new present.

Hint: Gift Locator
To find out if garbage or a present is approaching during one of your walks, look at the top screen. There should be the little dog symbol on the path that you drew. If that dog symbol stops and your dog is still walking, this indicates that either garbage or a present is coming up on the floor. If it is a present, tug your dog to a stop and your dog will notice it. It will pick it up and bring it over to you. It is easier to do this when your dog is running.

Easter Egg: Bulb Treat
When the light bulb appears, Use the stylus to drag the light bulb over your Nintendogs mouth. Your Nintendog will eat it. This has nothing to do with your Nintendogs hunger as it will do nothing to make it full or hurt.