The dog is a domesticated descendant of the wolf. Also called the "domestic dog,"" it is derived from extinct gray wolves, and the gray wolf is the dog's closest living relative. The dog was the first species to be domesticated by humans. Today, many of the dogs you know and love are the product of selective breeding between individuals with desirable traits, either physical or behavioral. For instance, around 9,500 years ago, ancient peoples began breeding dogs that were best able to survive and work in the cold. These dogs would become the family of sled dogs—including breeds such as huskies and malamutes— that remains relatively unchanged today.