What do you mean, bitch?

When the bitch grows and develops to a certain period, it begins to show sexual behavior, has secondary sexual characteristics, has reached maturity in reproductive organs and reproductive functions, has reproductive ability, and begins to estrus and ovulate normally. This is the sexual maturity of the bitch.

The age at which bitches reach sexual maturity after birth varies with breeds, geographical and climatic conditions, feeding and management conditions, nutritional level and individual conditions. In general, small dogs mature early, 8-65438+2 months after birth, and large dogs mature late, 12- 18 months after birth.

Dogs are domesticated by wolves. As early as the era of hunting and gathering, people have domesticated dogs as hunting assistants. So dogs are the earliest domesticated domestic animals.

Dog bones have been found in Cishan, Wu 'an, Hebei, Peiligang, Xinzheng, Henan and Hemudu, Yuyao, Zhejiang, which proves that it has a long history of domestication. ?

The dog-shaped scorpion unearthed from Sanlihe River in Jiaoxian County, Shandong Province is vivid and lifelike, which makes us see the morphological characteristics of domestic dogs in Neolithic Age. The dog bones unearthed from Anbanpo site in Xi 'an, Shaanxi, have smaller skulls, protruding frontal bones, smaller teeth and curved horizontal edge of mandible, which is quite different from that of North China wolves, indicating that the history of human domestication of dogs is indeed very early.