The Formosan Mountain Dog was originally kept by Taiwanese aborigines as hunting dogs, but now purebred Formosans are extremely rare and valuable. Since pure Formosans are extremely rare, there is a high risk of genetic disorders and unstable behavior due to the shallow gene pool. For this reason, crossing Formosans with other breeds occurred often due to the lack of pure females with steady traits. This is one of the major reasons modern Formosans look different, compared to old photos or documents from the early days. Some insist it is a natural change which does not affect the whole breed, while others actively fight to preserve the "pure" bloodline. Nevertheless, this breed is now popular all across the island as a watchdog and companion dog.
