Dog Family Tree Traced Back 2 Million Years

A new cache of extremely well preserved, prehistoric canine fossils is shedding light on dog and wolf ancestors from 2 million years ago to today.

The fossils, described in the latest issue of the Journal of Mammalian Evolution, date to that early period and belonged to a scrappy canine carnivore known as Canis etruscus that lived near Rome, Italy.

"Canis etruscus appeared approximately 2 million years ago and is the oldest European species referred to in the genus Canis," lead author Marco Cherin told Discovery News, adding that this species "was considerably smaller than the modern wolf."

"We can suppose that it was a social dog, as most of the living species of similar size," continued Cherin, who is a researcher at Perugia University's Department of Earth Sciences. "Hunting in packs, Canis etruscus could have preyed on small to medium-sized animals."

The prey of this carnivore, which looked like a cross between a German shepherd and a wolf, would have included animals such as ancient relatives of deer and pigs. They were all common at the site: Pantalla, Italy.

This apparent mother of all dogs in Europe likely gave rise to another member of the dog/wolf family tree, Canis mosbachensis, about 1 million years ago. Canis mosbachensis, in turn, is considered to be a direct ancestor of modern wolves.

Until recently, it was thought that dogs were domesticated from the gray wolf, but a separate study earlier this month countered that popular belief.

"The common ancestor of dogs and wolves was a large, wolf-like animal that lived between 9,000 and 34,000 years ago," Robert Wayne of UCLA, who was co-senior author of the study, told Discovery News.

That animal went extinct thousands of years ago and, as of now, remains unknown.

What is known about dog history is that the first canines came from North America, Cherin said. The earliest documented species from the genus Canis was Canis lepophagus, aka the "hare-eating wolf." Like the prehistoric canine from Italy, it was relatively small and had a narrow head.

Canines spread to Asia and then to Europe. It was in Eurasia at least 780,000 years ago that a dog relative might have encountered a member of our genus.

Eudald Carbonell, a professor at the University of Rovira and Virgili, told Discovery News that fossils of Homo antecessor -- an extinct human that looked a lot like us -- were found with fossils of Canis mosbachensis in Spain.

Could this very early human have enjoyed the companionship of the dog/wolf relative, or was the latter considered to be good eats or a predator? The fossil record so far, unfortunately, does not have those answers.

Carbonell and his team did find evidence for cannibalism -- for nutritional purposes -- among Homo antecessor individuals, so it's likely that this early, hungry human hunted the dog and wolf relative.

Read more at Discovery News