Dog

The dog, Canis familiaris or Canis lupus familiaris, also called the domestic dog, is a domesticated descendant of wolves, selectively bred by hunter-gatherers during the Late Pleistocene. Dogs and the modern gray wolf share a common ancestor, and DNA shows that all ancient and modern dogs descend from an extinct wolf population distinct from any modern wolf lineage. Dogs were the first species to be domesticated, more than 14,000 years ago and before agriculture, although genetic studies suggest the process may have begun over 25,000 years ago. Breeds vary widely in shape, size and colour, and all have powerful jaws with about 42 teeth. Through their long association with humans dogs gained the ability to thrive on a starch-rich diet that would be inadequate for other canids. The global population is estimated at 700 million to 1 billion.