The dog is a domesticated form of the wolf, a member of the Canidae family of the order Carnivora. The term is used for both wild and pets. The domestic dog has been one of the most widely kept working and companion animals in human history. Among the dog lovers, the word “dog” can also mean that the male of the canine species as opposed to the word “bitch” (the female of the species).
The dog quickly became ubiquitous in the culture throughout the world and has been very valuable for early human settlements. For example, it is believed that the migration of success through the Bering Strait would not have been possible without sled dogs. The dogs perform many functions for people, such as hunting, breeding, protection, companionship, and, more recently, helping the disabled. Currently, an estimated 400 million dogs in the world.
The duration of 15,000 years that was domesticated dog, which differs by only a handful of local varieties, animal groups with a similar morphology and behavior have been shaped by environmental factors and functions. As the modern understanding of genetics developed, humans began breeding dogs intentionally for a wide range of specific features. Through this process, the dog has developed hundreds of varied breeds, shows and more behavioral and morphological variation of all land mammals. For example, the height measured at the withers ranges from a few inches in the Chihuahua to a few meters in the Irish Wolfhound; color varies from white through grays (usually called blue) black and brown, light brown () to dark ( “red” or “chocolate”) in a variety of models, coats can be short or long-term hair like wool, straight, curly or straight.