Bryan Sykes belongs to the elite band of geneticists who can make their dizzying science at least partially clear to the layman. In this book he uses scientific knowledge of DNA and genome sequencing to shed light on how wolves became dogs.

About 40,000 years ago, Homo sapiens arrived in Eurasia, which was then dominated by tundra. Here modern humans encountered megafauna: mammoths, woolly rhinoceroses and many others. Among them was the precursor of the grey wolf.

By themselves, neither men nor wolves were capable of killing the megafauna safely, but there is plenty of evidence that even the very largest animals were successfully brought down. It is therefore conjectured that men and packs of wolves cooperated in hunting large game. Other examples of ‘cooperative hunting’ exist, and it is easy to imagine that the two species observed each other hunting and joined in, at first casually but subsequently more methodically. Men of this era had flint-tipped spears. A large animal, cornered by wolves, might well succumb to multiple spear wounds and yield enough meat for both men and wolves to share without fighting each other. From this, it is speculated, grew a hunting symbiosis of great importance to both species. The first unmistakable domestic dog fossil dates from 14,000 years ago, but anomalous canid fossils, dating from 31,000 years ago, have been found in France and Russia. Whatever its exact origins, by the end of the last ice age man had a canid companion that was no longer a wolf.

At the root of Sykes’s enquiry is the extraordinary intensity of the man–dog bond. A chapter by his wife, Ulla, provides eloquent testimony that people are more or less unhinged in their devotion to Canis lupus familiaris – a feeling reciprocated with equal fervour by the dogs themselves. He dismisses