Dogs evolved puppy-dog eyes
Every dog descends from wolves, and dogs were living alongside people at least 15,000 years ago — long before farming. Over that time they changed in a way that is written on their faces. A study in 2019 found that dogs have a small muscle above each eye that lets them raise the inner eyebrow, making the eyes look bigger and sadder. Wolves mostly lack it.
People respond to that look. In shelters, dogs that raised their eyebrows more often were rehomed faster. Scientists think the muscle developed because humans kept and fed the dogs who made the expression — which means the PUPPY face that gets a TREAT out of you was, in a sense, bred by people who could not resist it.
A nose that reads the world
A dog's sense of smell is many thousands of times more sensitive than ours, and a large part of its brain is given over to sorting smells. Dogs can pick out one scent in a mixture, follow a trail that is days old, and even detect some illnesses on a person's breath. A BEAGLE has one of the best noses of all, and beagles are used to sniff luggage for forbidden food at airports.
The wet leather of a dog's nose is also patterned with ridges and bumps, and the pattern is thought to be different for every dog, a little like a fingerprint. Sniffing is how dogs catch up on the news: a lamp post on a daily walk carries messages about every dog that has passed.
Most breeds are younger than you would think
Dogs have been bred for jobs for thousands of years — herding, guarding, hunting, pulling sleds — but most of the breeds with names and rules about how they should look were fixed in the Victorian era, after the Kennel Club was founded in London in 1873. Before then, a dog was usually described by what it did rather than what it looked like.
The names still give the jobs away. A RETRIEVER brings back game birds, a POINTER freezes and points at them, a TERRIER was bred to dig after animals underground, and a DACHSHUND, German for badger dog, has short legs for going down burrows. The HUSKY and SAMOYED pull sleds; the CORGI herds cattle by nipping at their heels; the MASTIFF and ROTTWEILER guard. Guide dogs are a job of their own, covered on our animal jobs page.
Spots, speed and small dogs
A DALMATIAN puppy is born pure white, and its spots only start to appear after a couple of weeks. The GREYHOUND is the fastest dog, reaching about 70 kilometres an hour in a sprint, and the WHIPPET is a smaller version bred for racing. The CHIHUAHUA is the smallest breed, and the tiny PUG was a favourite of Chinese emperors long before it reached Europe.
The rest of the grid is everyday dog life: a BONE, a LEASH, a COLLAR, a game of FETCH, a BARK, a wagging TAIL and a warm KENNEL, plus the LABRADOR, POODLE, BULLDOG, BOXER, COLLIE, SPANIEL, SHEPHERD and AKITA.