[1] They are well-adapted to the uneven and thickly forested terrain of Taiwan, having become a semi-wild breed prior to the arrival of several colonial reigns and foreign powers.

The medium type of the Formosan Mountain Dog has a shoulder height under 50 centimetres (20 in), with a firm and fit body, slim waist, big chest and half-covered ears.

Sung of the National Taiwan University and Mr. Ming Jie, Xu of the Formosan Dog & Guard Dogs Breeding Center (台灣犬護衛犬繁殖中心) described a typical Formosan as having almond eyes, firm jaw strength, black coating on the tongue, a triangular face, thin prick ears and a sickle tail.

If comfortable and well-trained, the Formosan will be friendly to people and other animals, though they tend to be a bit aloof or suspicious of strangers once they have bonded with their owner.

Sung Yung-yi that have been critical in the development of the Formosan Mountain Dog: the Dutch settlement of Formosa, the Japanese rule, World War II and the Kuomintang Era.

After the Dutch made Taiwan a colony, they began to import workers from Fujian and Penghu (Pescadores) as laborers, many of whom settled there.

The Dutch East India Company established a trading post whose main business was the export of sika skins to Europe.

During the six decades of Dutch activity 2,000,000 to 4,000,000 sika skins were exported to Japan and China,[10][11] contributing to the eventual extinction of the subspecies on the island.

The means of accomplishing this goal took three main forms: anthropological study of the natives of Taiwan, attempts to reshape the aborigines in the mould of the Japanese culture, and military suppression.

The east coast expeditions further provided a chance of crossbreeding Japanese dogs with the Formosans.At the end of World War II, for military purposes and preventing the U.S. Army from landing on the east coast of Taiwan, Japan started to build the Central and Southern Cross-Island Highway.

Furthermore, during this period, there was evidence showing that the Japanese military launched a massacre to reduce the population of the Formosan Mountain Dog.

Sung Yung-yi (宋永義) told a New Taiwan journalist: "Formosan dogs are very smart and agile, but they are more primitive animal, and do not want to be caged.

Using sanitation as an excuse, Japanese military launched a large-scale massacre of Formosan to reduce the local dog population."

During the time when the Japanese military was building the Central and Southern Cross-Island Highway, they were constantly encountered by the aborigines.

Sung Yung-yi believes that the true reason that led to the Formosan Mountain Dog's near-extinction is the dog-eating culture.

[6] The introduction of a variety of foreign dogs to Taiwan in the past was also a big threat to preserving the bloodline of the Formosan.

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.

Sung's request was made because he and his colleagues had difficulties in finding pure-blood Formosan Mountain Dogs during his five-year studies from 1976 to 1980.

In order to find a sufficient population for his study, he located 29 Taiwanese aboriginal villages in the mountain ranges and initiated a mass search.

This number alerted the Food and Agriculture Organization (FAO) of the United Nations, as the animal was close to extinction.

Sung believed that a Formosan Mountain Dog rehabilitation program should be encouraged by government efforts and carried out by careful planning.

For instance, it was often found that German Shepherds who perform intensive security duties on a daily basis will suffer from serious bruising on their paws.

After half a month of testing, the ROC Air Force concluded that the Formosan Mountain Dog's senses of smell and hearing, dexterity and alertness towards strangers were all more suitable for the purpose of guarding their fighter jets.

In the 1980s he started a business dedicated to creating a purebred Formosan close to the one in his childhood memory, beginning with a single puppy that he purchased for NT$30,000 (about US$910.00) from an aboriginal man.

Further, it is also due to the subjective preferences of breeders and their belief of what the pureblooded Formosan should look like, which they created a different trend of the "pure-blood."

Such breeders also applied the "new type" of Formosan Mountain Dogs to the FCI to develop a "standard", which may be very different from what it originally should have looked like.

[23] Breeders also created a conflict in debating for the future of the Formosan Mountain Dogs, as maintaining its purity or modifying through hybridizing it into a new type.