Nintendogs is a real-time pet simulation video game developed and published by Nintendo for the Nintendo DS handheld video game console. It was first released in Japan, and was later released in North America, Australia, Europe, and other regions. As of 2009, in all versions combined, it had sold 21.67 million copies making it the best selling standalone game. It was originally released in three different versions - Dachshund & Friends, Lab & Friends, and Chihuahua & Friends. It has been re-released twice since then - first as a bundled release with a special edition Nintendo DS with a new version called Nintendogs: Best Friends, and then later as Nintendogs: Dalmatian and Friends.Nintendogs utilizes the Nintendo DS' touchscreen and built-in microphone. The touch screen allows the player to pet his or her dog, and also allows for him or her to use various items that can be found or purchased. These range from balls and frisbees, to toys, to grooming supplies to keep the dogs happy. The microphone is used to call to the player's dog by speaking the name given to the dog in the beginning of the game as well as to teach the dog commands such as "sit" or "roll over". Players can bring their dogs on walks and to the park if they so choose. They may interact with other players in multi-player by using the DS' wireless link-up. It also uses the DS' internal clock and calendar to allow the dog to grow hungrier or dirtier based on the elapsed time.Nintendogs received mostly positive critical reception. It has an aggregate score of 85% at Game Rankings, and has won many awards, including the 2006 Innovation Award from PC World and Best Handheld Game from the Associated Press. As of September 30th 2008, all versions of Nintendogs combined have sold 20.03 million copies worldwide. Because of Nintendog's success, Nintendo has made several related products, including Nintendogs toys and a series of Nintendogs trading cards.