It has been more than 50 thousand years since ancient primitive people hunted dogs and began to raise dogs. According to zoologists' speculation, dogs are the earliest domesticated domestic animals. What can be found now is the late paleolithic. The earliest recorded cases are Iraq and Israel, about 12000. Others are the United States (10400 years ago) and the former Soviet Union (9000 years ago). In China, dogs have been pets for more than 2,000 years.