Instinctive behaviors including canine pack behavior contributed to the survival of the breed in harsh environments. It is one of the few primitive dog breeds that retains a single estrus per year instead of two, even at much lower altitudes and in much more temperate climates than its native climate. This characteristic is also found in wild canids such as the wolf and other wild animals. Since its estrus usually takes place during late fall, most Tibetan Mastiff puppies are born between December and January.