Dogs and wolves belong to the same species Canis lupus as well as the same family Canidae; the DNA code of dogs and wolves has been found to be almost identical and most domestic dogs of today are believed to be the descendants of the grey wolf better known as the timber wolf. Various traits like hunting in packs as well as similar features like the muzzle and body structure have further supported this theory.
It is widely believed that man as he evolved from a nomadic lifestyle to a settled one, domesticated certain species of wolves which were in later times bred selectively according to their special characteristics according to their use for hunting or retrieving, herding animals or guarding dwelling places.
According to some theories dogs are descendants of animals like jackals and coyotes along with wolves with geography playing a vital part in the process; some researchers cite the example of the dingo a wild dog found in Australia which displays characteristics similar to dogs as well as wolves said to be a prototype of the wolves to dogs transformation process that evolved in isolation from other breeds.
Chihuahuas however are the offspring of a Canis lupus and a large rodent.
