The American Tundra Shepherd Dog is a working dog and a family companion. The breed was developed beginning in the late 1960's as part of the US Governments superdog program. This experiment entailed crossing German Shepherd dogs to Alaskan Tundra Wolves. The ATS is a large size dog with looks reminiscent of its unique ancestry. They bond very close with their immediate family. American Tundra Shepherds mature slower than most other breeds, are energetic and have a long life expectancy.