Tibetan mastiffs were developed in the Himalayas to guard people and their property, but today they are some of the best guard dogs in the world. Tibetan mastiffs are intelligent, are very alert, and are very strong-willed. They are also very territorial. Do not forget that if you have a Tibetan Mastiff in your home, no one else will be able to visit without the Mastiff bothering them. They're also very pricey.