It is believed that the Shih Tzu originated from across breeding of the Tibetan Lhasa Apso and the Pekingese in the mid - 17th century and were highly prized by Chinese royals, so much so that they refused to trade the dogs. The Chinese guardian lion at Mount Emei is thought to be a Shih Tzu. The name Shih Tzu means 'lion dog' in Chinese.
The US and UK Kennel Clubs recognise different Shih Tzu. In the US their front legs are straighter and their rear legs are more muscular, the head is larger and the shoulders are more to the front of the body.
As a pet, the Shih Tzu is alert, generally happy, gentle and loyal and likes to be around people. Lack of proper training and regular exercise could lead to the dog being snappy at people especially children and bark a lot.