According to Pat Shipman, dogs have been humans' faithful companions for more than 32,000 years. Around this time, the Neanderthal man -- who had previously occupied present-day Europe for a staggering 250,000 years -- became extinct.
He says these two facts may be related -- and it was humans' close friendship with canine associates that tipped the balance in favour of modern man.
Shipman said the advantages that domesticating a dog brought for modern humans were so fundamental to evolution, that it made people "top dog" out of the competing primate species, the 'Daily Mail' reported.
He analysed the results of excavations of fossilised canid bones from Europe, during the time when humans and Neanderthals overlapped.
The research first of all established a framework to "best friend" relationships with early humans adding dog teeth to jewellery, showing how they were worshipped, and rarely adorning cave art with images of dogs -- implying dogs were treated with a reverence not shown to the animals they hunted.
The advantages dogs gave early man were huge -- the animals themselves were likely to be larger than our modern day pooches, at least the size of German Shepherds.
Because of this, they could be used as "beasts of burden", carrying animal carcasses and supplies from place to place, leaving humans to reserve their energies for the hunt. In return, the animals gained warmth, food and companionship, or, as Shipman puts it, "a virtuous circle of cooperation".
In short, Shipman said: "Animals were not incidental to our evolution into Homo sapiens -- they were essential to it. They are what made us human."