The Pomeranian (often known as a Pom) is a breed of dog of the Spitz type that is named for the Pomerania region in north-west Poland and north-east Germany in Central Europe. Classed as a toy dog breed because of its small size, the Pomeranian is descended from larger Spitz-type dogs, specifically the German Spitz. The merle Pomeranian is a recent colour developed by breeders. It is a combination of a solid base colour with a lighter blue/grey patch which gives a mottled effect. The most common base colours for the effect are red/brown or black, although it can also appear with other colours. It occurs when the rings that normally hold the shape of the windpipe collapse, closing the airway. The symptoms of a collapse include a honking cough that can sound similar to a goose honk, an intolerance to exercise, fainting spells and a cough that is worsened by hot weather, exercise and excitement. The tendency for episodes of tracheal collapse typically increases in frequency and severity as the dog ages.