No other species of animal displays as much diversity as the domestic dog. Today there are over 400 breeds of dog to choose from, in every shape and size, not to mention cross breeds. Despite so much variation, all domestic dogs are part of the same family (Canis lupus familiaris) and DNA analysis has shown they are all descended from the gray wolf (Canis lupus).

The wolf proved itself to be well prepared for adapting to a domestic life and dogs became very useful to early human beings. Their adaptability meant they had many uses and roles alongside humans including herding, guarding, hunting and pulling sleds; and they even have a religious role in some faiths (e.g. Hinduism).

Today there are more than 400 million dogs around the world, compared with only about 40,000 wolves left in the wild and in recent years dogs have gained a new role as pets as well as working dogs.

It is likely wolves were first domesticated around 15,000 years ago, although some researchers have suggested that this occurred even earlier. Humans and wolves befriended each other when wolves were foraging around our Mesolithic camps for food, and our own ancestors quickly discovered that 'dogs' could help them track and hunt animals.

The wolves that were most tolerant of people thrived. Once a village had a resident population, humans recognised that young wolves could be socialised and put to useful purposes. We began by selecting them for their friendliness and then to breed them for physical and behavioural characteristics. We bred our 'wolf' specifically to enhance useful behaviours. The wolf remains the best general all-rounder, but some breeds of dog have evolved so they are now far better at certain jobs than their ancestors. For example, the Bloodhound can track a scent better, a German Shepherd guards better, a Greyhound is faster, Terriers are more tenacious, and the Cavalier King Charles Spaniel fits much better on your lap than a Timber Wolf ever can!

By 7,000 BC breeding was widespread. The first recognised 'breed' probably resembled a swift, lanky greyhound, developed for its speed in hunting. As time went on, humans bred more specialist skills, such as Sighthounds and Scenthounds. Shapes and sizes evolved accordingly: shorter muzzles, shorter legs and acute hearing and sight. So much breeding went on that by the time of the Roman Empire most of today's general breed types were already identifiable.

It is important to remember that, although it has been a very long time since your Cocker Spaniel's forebears roamed the forests, all domestic dogs today retain many of the behavioural characteristics of the young wolf, including playfulness, an urge to explore, and a willingness to submit to a parent or leader figure. The ability of the wolf to vary its social organisation from living alone to living in pairs or in large packs, its excellent communication abilities, and its need to develop stable communal relationships have also been passed on to the dog, making them the great family pets they are today. However, they never quite forget their wild origins and we must consider this when thinking about training or behavioural problems.