The eldest My Little Ponies are called G1 ponies and are easy to recognize by their chubby body and they have a symbol on both their hips. G1 ponies were last produced in 1995.
G2: 1997-2003
After two years of silence around My Little Pony it was time for a new generation: G2 ponies. They are smaller and thinner than the G1 ponies and they all have a little diamond in their eyes. Just like the G1 ponies, the G2 ponies have a symbol on both of their hips, with exception of a few baby ponies. All G2 ponies were sold with several accessories.
G3: 2003-2011
On request of many G1-fans in 2003 there came an end to the G2 ponies and a new series came out who looks more like the G1 ponies: the G3 ponies. G3 ponies are a bit slimmer and have a symbol on only one hip. G3 ponies from 2003-2007 have a magnet under the hoof on which you can find a little symbol (a hoofheart). With this magnet, you can activate accessories and playsets. As of 2008 the G3 ponies don't have a magnet anymore. Instead of a hoofheart they have a clothes-hanger on one leg. This means that they can wear the plastic dress-up sets that were available as of 2008.
G4: 2010-present
In 2010 a new series was released: Friendship is Magic. These G4 ponies are smaller than the previous generations. The series consist of a mix of old and new characters (e.g. G1 Applejack and G3 Pinkie Pie) and ponies that have changed slightly (e.g. Rainbow Dash was an earth pony, but is now a pegasus).
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