Barking Up Your Dog’s Family Tree

The Great Dane who thinks he’s a lap dog; your bouncy ball of fur whose tail wags her entire backside; and the terrier digging holes right now in your backyard all are cousins of the wolf, something you may already have known, but did you know that:

1. The Canis familiaris, the dog, did not evolve from the North American gray wolf, television commercials notwithstanding, but the two likely diverged from a common extinct ancestor, the canid, nearly 40,000 years ago?

2. While scientists used to think dogs were domesticated about 14,000 years ago, new evidence suggests the figure could be closer to 33,000 years?

In the last 15 years, scientists have utilized DNA sequencing to overturn earlier assumptions about the dog’s evolution. Not long ago, it was believed that the dog was first domesticated in Eurasia, but a 2014 study looked at three gray wolves: One each from China, Israel and Croatia, places were dogs were thought to have originated, and also two dog breeds that largely have been isolated from modern wolves – the basenji and dingo. Findings showed the dogs were more related to each other than the wolves.

“The common ancestor of dogs and wolves was a large, wolf-like animal that lived between 9000 and 34,000 years ago,” Robert Wayne, UCLA professor and co-senior author of the study said on Discovery News. “Based on DNA evidence, it lived in Europe.”

The dog’s story of evolution is being rewritten through the use of genome sequencing. But to the dog lover, this story transcends science; it is a poetic and heartfelt event. Thus, the following tale of your furry buddy’s evolution injects a little love into the plot line.

Once upon a time, way back in the Eocene epoch of 65 – 55 million years ago, there lived the beautiful Miacis, a weasely-looking, eight-inch long, five-toed carnivore, but beauty is in the eye of the beholder. Appealing or not, the genus Miacis is pivotal in the evolution of both caniforms (dog/wolf) and feliformia (cats/hyena/civet). How intriguing to imagine a common ancestor of both Lassie and Puss ‘n Boots!

The Miacis’ sharp, retractable claws, long bodies and short limbs enabled them to live mostly in trees, munching on insects, birds, reptiles and eggs while also avoiding large ground predators. This magical mammal is the genesis of many creatures, from the raccoon to the fox jackal … to the modern dog.

Barking Up Your Dog's Family Tree  Genus miacis of North America and Europe.

Evolution gets a boost during the Late Eocene epoch, about 40 million years ago, when Hesperocyon, the most ancient and direct ancestor of all canidae, from wolves and dogs to foxes and jackals, walked the earth. Three feet long and almost 20 pounds, Hesperocyon, king of the canidae, populated North America and thoughtfully left behind fossils at Los Angeles’ La Brea Tar Pits.

Moving to 30 million years ago, we find Miacis’ descendant, the Cynodicius elegans, or “in-between dog,” Once thought to be history’s first dog, today’s scientists have since changed their minds.

Barking Up Your Dog's Family Tree

Sometimes called the “bear-dog,” the Cynodictis  walked on its whole foot, like a bear or human, rather than on its toes, as do wolves and dogs.

Consensus now suggests that the realm’s first true canine and most likely our dogs’ earliest ancestor, appeared about 34 million years ago: North America’s Lepotocyan, (Greek for “slender dog). This foxlike canine thrived for an astounding 25 million years. Even more importantly, his immediate descendant is the star of our story: The Eucyon, or, “original dog.”

From North America, the Eucyon traversed into South America as well as using the Bering land bridge up north cross over into Eurasia. Bridges go both ways, of course, so while the Eucyon was exploring Europe and China, larger wolves from Europe and China crossed the Bering land bridge and invaded the Americas. In a flash, (three million years), the Eucyon diverged into the wolf, coyote and dog.

Barking Up Your Dog's Family Tree

A Eucyon: fossil remains of the foxlike carnivore have been found in Texas, Oregon and Nebraska.

The eucyon probably would have avoided the Canis dirus, the dire wolf, a relative of sorts, rather like a great uncle several-times-removed from the dog, but weighing up to 200 pounds and with impressive fangs – the better to bite you with, my dear – and possessing a bite strength 129% greater than the modern gray wolf. Worthy of its mythical status, by the time the last Ice age ended 10,000 years ago, the dire wolf was extinct, unless you watch television’s “Game of Thrones,” which features its version of the terrifying predator.

Barking Up Your Dog's Family Tree

Two dire wolves mired in the La Brea tar pits, while fighting Smilodon over a Columbian mammoth carcass. Fragments representing over 4000 individual dire wolves have been retrieved from the La Brea Tar Pits in Los Angeles, CA, but fossil remains of the wolf range from Canada to Bolivia.

The dog and the gray wolf survived. And the dog was about to become not only tame, but trainable and even reliant on humans: domesticated.

Domestication of the dog. The very concept has the comforting feel of a fairy tale. And it does go way back in terms of human history. Excavation of a cemetery in Jordan dating back as far as 15,000 years contains the remains of a woman with her hand resting on a puppy. The magic that binds human to dog started long ago.

We believe the momentous partnership began when early humans were still hunter-gatherers, predating the development of agriculture. The common need to hunt for food created a symbiotic opportunity: Dogs had a keener sense of smell to detect prey and the human had weapons to bring down larger animals than a pack of dogs or wolves could.

Most likely, it happened in various places: The Near and Middle East, China, and Europe, but probably first in the warmer southern climates, such as Afghanistan, India and North Africa, where the canines were smaller and thus less able or likely to prey on young children.

Wolves and dogs scavenged scrap food near human encampments. Conversely, humans studied the way the canines hunted. Dogs learned that living near humans provided them a consistent source of food as well as safety from predators. Humans saw that hunting with dogs was more efficient; that dogs kept their camps clean of food scraps; they made superb intruder alerts; could provide warmth in winter and, in a pinch, were a convenient source of meat. Over time, the dog’s calmer, nonaggressive nature received greater cooperation from humans, i.e., more food and attention to needs. And that’s not even counting the joy of playing with adorable puppies. Wolves on the other hand, simply weren’t “wired” to be playful or to attach themselves to humans.

The Canis lupus, was unsuccessful at domesticating for genetic reasons. Noted veterinary behaviorist and professor at Tufts’ Cummings School of Veterinary Medicine, Dr. Nicholas H. Dodman, explains in an interview from nationalgeographic.com: “Wolves and dogs are actually quite similar when they’re very young: They both do the same playful behavior, run around in circles and generally look cute. Little wolf puppies will even bark like a dog. But suddenly the wolf grows up and becomes aloof and lean and suspicious.”

The dog, meanwhile, simply kept adjusting through the years, even when the Homo sapien changed from being hunter-gatherers and developed an agricultural society during the Neolithic Age. Remarkably, the dog evolved a genetic mechanism to digest the carbohydrates now added to his diet in the starchy grains that his humans were farming.

Apparently, even after 40 million years of evolution, your dog will do what it takes to be part of your life. Now that’s a happy ending.

By Lisa Bowman