Speaking of Dogs

Doggies' daddy

German researchers announced this week that they've got a border collie named Rico who knows more than 200 words and can learn new words as quickly as small children do. Of course, Rico doesn't exactly speak German. Rather, he knows which objects "map" to the words he knows.

In fact, Rico appears to be capable of what psychologists call "fast mapping"--quickly figuring out that a previously unknown object and a previously unknown word go together. It's a technique children use to learn new words, and until now scientists thought only humans could do it.

Maybe Rico is the bard of the border collies, but dog lovers won't be too surprised at his semantic skills. After all, some of us have been communicating with our canines for years. How else do you think they became our best friends?

How the "Big Bad Wolf" Became
"Man's Best Friend"

Scientists used to think that the wide variety of domesticated dogs--more than 400 recognized breeds--were variously descended from wolves, jackals, and coyotes. But most experts now believe that virtually all of our pampered pooches, from the smallest chihuahua to the most massive mastiff, are the progeny of Eurasian grey wolves.

In fact, mitochondrial DNA evidence suggests that our furry friends are all descended from just a few female wolves that lived between 40,000 and 15,000 years ago. But how did humans ever get those wolves to come, sit, and stay? There's still plenty of dispute on that question, but the story goes something like this.

Step 1: Be Tolerant

Wild dogs and humans likely learned to tolerate each other long before domesticated dogs arrived on the scene. Semi-wild dogs co-exist with humans in many underdeveloped areas even today, scavenging for scraps of food and sometimes hunting vermin while the humans around them go about life.

Such semi-wild dogs are only a short step from being tamed, and--as an ongoing Russian study shows--tame dogs can quickly turn into pets. Since 1959, Russian scientists have selectively bred a group of Siberian foxes for one trait: tameness toward humans. Their foxes now seek out human attention, lick their handlers, and wag their tails like lap dogs. (No word on when the foxes will fetch the Russians' slippers.)

Step 2: Keep an Open Mind

Sometime after dogs got used to being around humans, they figured out how to read our gestures and expressions--and it wasn't just that we taught each new brood of pooches to do it. Even 9-week-old puppies are better than adult chimpanzees at reading social cues from humans, strongly suggesting that dogs' people-reading skills are innate.

Our minds are open books to our domesticated canine companions--but only to them. Despite their genetic similarity to dogs, wolves and other wild dogs are oblivious to these social cues.

Step 3: Adapt to Changing Needs

Once dogs had learned to tolerate us and read our minds, it was only a matter of time before we put their powerful ears, noses, and teeth to work. Though much of the timeline of dog domestication is still in dispute, it's clear that dogs had become an important part of human life by the Bronze Age (around 4500 B.C.), if not long before.

Bronze Age depictions of dogs hunting with humans have been discovered in Europe, the Middle East, and North America. Statues of dogs often guard ancient tombs and crypts. And at least five major types of dogs show up in the fossil record around that time: mastiffs, sight hounds (like greyhounds), pointers, herding dogs, and wolf-type dogs.

Over the years, humans have bred dogs to suit all sorts of needs--from tracking and retrieving game, to herding livestock, to making us feel loved and appreciated. And yet, all domesticated dogs still share roughly 99 percent of their DNA, so, believe it or not, only slight genetic differences separate great danes from toy poodles. The genes that separate cat lovers from dog lovers remain unknown.

Want to learn more?
Meet "Dogs and More Dogs" at PBS.org