Domestic dog

Dogs live with people all around the world.

They live in cities, in the countryside and on farms. Some dogs even pull sleds in the snow.

Dogs live with people worldwide, on every continent except Antarctica. You can find them in city apartments, farms, deserts, rainforest villages and the frozen Arctic, wherever people live.

Dogs came to the Americas with people, probably about 10,000 years ago. Some dogs live without owners. These are called feral dogs, and some of them live in family groups much like wolf packs.

The domestic dog has no wild range of its own: Animal Diversity Web describes it as found in association with humans worldwide, in a wide variety of habitats, on all continents except perhaps Antarctica. The map therefore shows the continents where dogs live with people.

Genetic evidence suggests dogs did not arrive in the Americas with the first people more than 15,000 years ago, but only some 10,000 years ago. Feral dog populations exist in many places; some have reverted to wolf-like family packs in which a dominant pair breeds and other members help raise the pups.

Long, long ago, all dogs were wolves.

Some wolves followed people and ate their leftovers. Slowly, these wolves became friendly dogs.

The dog's wild ancestor is the gray wolf. Scientists think that tens of thousands of years ago, some wolves began following groups of hunters across northern Europe and Asia, eating the scraps they left behind. Over many generations, the friendliest ones became the first dogs.

The first dogs were hunters with sharp eyes and noses. Later, people bred dogs for different jobs: guarding, herding sheep, pulling sleds, hunting and keeping people company. That is how so many breeds came about.

Genetic studies indicate that dogs descend from now-extinct wolf lineages that split from the ancestors of modern wolves between about 27,000 and 40,000 years ago, and that the first domestication events took place in northern Eurasia between about 14,000 and 29,000 years ago. Wolves probably took the first steps themselves by trailing nomadic hunters and scavenging their kills.

Britannica stresses that domestication was a process over thousands of years, with dogs and wolves continuing to interbreed and early dog populations replaced by later ones. Regional studies point to early dogs in China and India, and the timing and place remain debated. Early dog types included mastiffs, wolf-like dogs, sight hounds, pointers and herding dogs.

Dogs like to eat meat, but pet dogs eat dog food too.

Puppies need to eat several times a day. Grown-up dogs eat once or twice a day.

Dogs are carnivorans, members of the meat-eating group of mammals, and their teeth are like their wolf ancestors' teeth. Pet dogs eat food made for dogs, which gives them the right mix of protein and energy.

Puppies grow fast, so they need much more food for their size. A puppy needs about twice as much protein as an adult dog for each kilogram it weighs, and is fed four times a day until it is three months old, then three times a day until six months.

Dogs retain the carnivoran dentition of wolves, with 42 adult teeth, though domestic dogs are fed a varied diet by people. Animal Diversity Web notes that growth sharply increases needs: puppies require about twice the protein and 50 percent more calories per unit of body weight than adults.

Feeding schedules reflect this: about four meals a day until three months, three until six months, and two thereafter. An average-sized adult needs roughly 30 kilocalories per pound (about 66 per kilogram) of body weight a day, with real needs varying by breed, age and activity.

Dogs talk with their tails, ears and faces.

A wagging tail and a relaxed face say, let's play! A tucked tail says, I feel scared.

Like wolves, dogs are pack animals, and they talk with their whole bodies. A friendly dog has a relaxed face, a slightly open mouth, ears loosely back and a wagging tail. A dog inviting you to play lowers its front end, keeps its rear up and may bark.

A dog that feels threatened may raise its fur, show its teeth and growl. A frightened dog pulls its ears back and tucks its tail under its body. Watching a dog's body helps you know how it feels.

Dogs share with wolves a complex repertoire for signaling social position and mood. Animal Diversity Web describes greeting (relaxed face, mouth slightly open, ears loosely back, tail wagging), offensive threat (raised hackles, bared teeth, wrinkled nose, growling, tail high) and defensive threat (growling but with ears flattened and tail low), as well as submission with averted eyes and a 'submissive grin'.

A wagging tail is therefore not always friendly: it can accompany an upright, threatening posture. Reading the whole body, ears, mouth, tail and stance together, is the reliable way to interpret a dog, and it is the basis of safe behavior around dogs for children and adults.