The monumental Tibetan Mastiff was initially bred to be the guardian of herds, villages, palaces, flocks, tents, and monasteries. There are two types of Tibetan Mastiff, distinguished by their appearance: There is the Tsang Khyi which is known as the monastery dog. Generally, the Tsang Khyi is taller, has thicker bones and is heavier than the second type, the Do-khyi, or nomad dog. 
Tibetan Mastiffs can be formidable beasts and have even been known to confront wolves and still win the battle. The powerful and athletic build of these dogs allows them to be impressively agile and strong. These dogs were bred to be guardian dogs and not necessarily guard dogs. This means that this dog is not particularly good at taking instruction from its owner, rather they prefer to guard independently. Furthermore, this dog was trained to bark when everything was safe, not vice versa. Therefore, do not be surprised that your dog may bark throughout the night to let you know that everything is fine. 
In fact, they are even more aware, active and alert at night. They tend to keep intruders and strangers at bay simply by their appearance. This even-tempered breed is also known to be fearless and courageous when protecting their families.  These dogs should not be raised in a house without a backyard.
As dogs bred to protect their families, it is not surprising that these dogs are reserved toward strangers. They are also intelligent, but can be stubborn and willful at times. Thus, they need to be trained. They can be very aloof and suspicious towards strangers, but to their families they are devoted and passionate. In fact, they can be gentle and patient with children. Toward other dogs, they are usually friendly and rarely aggressive. However, for inexperienced dog owners, the Tibetan Mastiff is not an ideal choice.
Compared to other large breeds, Tibetan Mastiffs are found to be less susceptible to severe health conditions. Research further shows that this breed can live up to 14 years. In China, the Red Tibetan Mastiff has become a status symbol. Owning a Red Tibetan Mastiff has been a way for the Chinese to show off their fortune, instead of using cars and jewelry. In fact, it is considered to be the most expensive dog breed in the world. 
Check out this video from AnimalPlanetTV if you want to learn more about the Tibetan Mastiff… and get ready to fall in love with this adorable, lovable and highly dependable breed of dog.
 Zak Ming, The Complete Guide to Tibetan Mastiff (Kevin Winslet of For Dogs Sake®, n.d.), p. 17.