The Pražský krysařík (Prague Ratter) is a small breed of dog from the Czech Republic that is rarely seen outside its country of origin. It is the smallest breed in the world by breed standard, because of the maximum height of the dogs, unlike Chihuahuas who are measured by weight.
The breed was popular in central European royal palaces in the Middle Ages. It was already an established breed by the time of the rule of the Polish king Bolesław II the Generous (1058–1081). He became fond of the Ratter and had two of them imported from Bohemia. As their name suggests they were also commonly used as rat catchers in rural and urban households.The popularity of the Prague Ratter started decline in the 19th century when the Miniature Pinscher became more fashionable. The breed went through a renaissance in the 1980s as Czechs and Slovaks started to breed them again.It is not yet an Fédération Cynologique Internationale acknowledged breed, as there is only about 2500 Prague Ratters registered and they usually only have 1-3 puppies per year. They are nevertheless presented at shows in the Czech Republic and Slovakia.
Subject to bone injuries due to their small size. Also subject to patellar luxation, an ailment common to small breeds. Krysariks can also have retained baby teeth which may need to be pulled to prevent further problems with dentition.
The Prazsky krysarik has a life span of 12 to 14 years.