The Ultimate Dog Book - Hardcover

Chapter 1

Origins and Domestication

About sixty million years ago, a small mammal rather like a weasel or polecat clambered through the primeval forests. Its name was Miacis and it was the ancestor of the group of animals that we call canids: the dog, jackal, wolf, and fox family.

Unlike modern dogs that walk on their toes, Miacis was fiat-footed. It had a carnivore's teeth and a smallish brain, but was more intelligent than its contemporaries, the creodonts, another group of primitive meat-eaters. The creodonts were much more common than Miacis, but gradually became extinct, the last one dying out around twenty million years ago.

Canine ancestors

By around thirty-five million years ago, Miacis had given rise to a variety of early canids. We know of over forty types, some like bears, some like hyenas, and some like cats. Some, however, were like dogs: Cynodictis, for example, resembled a primitive Cardigan Welsh Corgi. These dog-like canids were the only ones to survive the evolutionary process, and some of them provided the basis for the domestic dog.

Dogs as we know them first came on the scene in Eurasia between 12,000 and 14,000 years ago. From what kind of animal did they directly spring? It was originally thought that their ancestor was a form of jackal or jackal/wolf cross. Scientists now believe, however, that it was the smaller southern strain of the gray wolf (Canis lupus pallipes) still to be found in India. During the period in question the gray wolf (despite its name, an animal with a wide variety of coat colors) was distributed throughout Europe, Asia, and North America.

Other possible dog ancestors include the woolly wolf of northern India and Tibet and the desert wolf of the Middle East. It is, however, certain that all domestic dogs sprang from one of these sources (or possibly more than one, in parallel development), and that they are not genetically connected with any other species.

Dog diversification

Because of their intelligence, versatility, and use of social co-operation within the pack, wild dogs spread quickly all over the world. The Dingo, however, which many believe was the basic type of Canis from which the modern dog evolved, was already domesticated when it was introduced to Australia thousands of years ago by the first immigrants. Wild dogs were probably domesticated in different ways in different parts of the world; some while scavenging for food around human settlements, others when early man hunted dogs for food and took litters of puppies back to the homestead for fattening up.

From bones and fossils found around the world and dated back to about 6500 years ago, we can say that at that period there were five different types of dogs: Mastiffs, wolf-like dogs, Greyhounds, Pointer-type dogs, and sheepdogs. Since then, thousands of breeds have been developed by both artificial and natural selection. But over the centuries many have been lost, and only about 400 remain today.

When the Europeans first arrived in North and South America in the fifteenth and sixteenth centuries, for example, they found at least twenty distinct dog breeds: now the Mexican Hairless, Eskimo Dog, and Peruvian and Chilean Wild Dogs are among the few surviving natives. Other ancient breeds include the Basenji, native to Africa, and, from the Middle East, the equally venerable Saluki and Afghan.

Design and Anatomy

The dog is essentially an animal of the chase: enduring, patient, intelligent, and fleet of foot. Above all it is a sociable beast, with none of the aloof, lordly, go-it-alone attitudes of the cat family. This is clearly seen in the behavior of packs of wild dogs, which not only co-operate in setting up group ambushes, but also make sure that unattached adults contribute to the community by acting as baby-sitters while parents go hunting.

The dog family, which includes foxes, jackals, and wolves, is not highly specialized biologically. In fact, its broad adaptability and multipurpose form have been major factors in its survival worldwide. Nevertheless, it is important to consider some of the dog's systems which contribute to its ability to survive and which are generally common to Dingo and Dachshund, Chihuahua and Cocker Spaniel.

Locomotion

It is a well-known fact that the cheetah is the world's fastest land mammal, achieving speeds of possibly up to 80mph (129km/h) over short distances. The fleetest members of the dog family are not in the same league, although wolves can achieve speeds of around 35mph (56km/h), and Salukis and Greyhounds bred specially for racing can approach 43mph (70km/h).

But hunting in the animal world is often carried out over long distances. Here is where the stamina of the dog family pays dividends. African Wild Dogs will pace one another, some loping behind for a while as others race ahead. When the leaders tire, the lopers move to the front and keep up the relentless pace of the vanguard. After a long chase this species may actually run down and kill lions.

In the water the dog is generally a no more than adequate swimmer, employing the paddle stroke named after it. One canine, however, really is an excellent swimmer and diver. This is the wild Raccoon Dog of China, Japan, and Siberia. An expert at fishing, the Raccoon Dog can stay underwater for several minutes when in pursuit of prey.

Senses

A dog has the same senses as a human, but they differ markedly in power. This is because of the different needs of our respective ancestors.

Smell

Dogs have a very powerful sense of smell. Although it varies from breed to breed and among individuals in any one breed, their olfactory ability is outstanding and far superior to our own -- in fact about one million times better. Only eels are notably better smellers than dogs, while butterflies have a sense of smell approximately equal in sensitivity, but can use it at much longer distances. Dogs are used in France and Italy to find the truffle fungus, which grows up to 12in (30cm) underground, and in Holland and Denmark to detect gas leaks. They are more sensitive than the most advanced of odor-measuring machines, and are used all over the world to search for explosives, drugs, and people. How do they do it?

Smells consist of molecules of particular chemicals floating in the air. When these molecules land on the special olfactory membrane inside a nose, nerve impulses convey the "smell information" to a particular part of the brain. This olfactory center is highly developed in the dog and far larger than in man. The olfactory area in the adult human nose is about 1/2 sq. in (3cm2), whereas in the average canine nose it covers almost 20 sq. in (130cm2), being arranged in folds in order to filter smells from the incoming air. To accommodate such a structure, dogs have developed long noses (with some exceptions among the recent "artificial" breeds). There are also many more sensory cells in the dog's olfactory membrane than there are in the human's. We have five million sensory cells. A Dachshund has 125 million, a Fox Terrier 147 million, and a German Shepherd 220 million.

A wet nose helps in smelling: it dissolves molecules floating in the air, bringing them into contact with the olfactory membrane, and clears old smells away. Pigment helps too, but how this works is not understood. The pigment is not in the sensory cells but nearby: the nasal membranes of the dog are dark, and the black pigment in the nose pad may also play some part in improving the dog's sense of smell.

Tracker dogs take advantage of the fact that the sweat of every individual human is as unique to him as his fingerprints. A dog can recognize the "scent image" of a person and make deductions from the evaporation of various ingredients of the smell with time. This allows it to run along a trail for a few yards, register the change in the image, and thus even determine which way the person was going.

Taste

The dog's sense of taste is relatively poorly developed, compared with man's. This is probably because, unlike man's ancestors, vegetarian primates that can select from a range of foods in front of them, dogs are carnivores that spot their prey at a distance, and have to eat what they can catch.

Vision

A dog's sight is well adapted to hunting small, fast-moving animals. Most species do not hunt primarily by sight, however, and often miss creatures that stand still. Certainly dogs are not sensitive to color, and see mainly in black, white, and shades of gray.

Hearing

This is something else at which dogs are excellent. Although some breeds have better hearing than others, most dogs are equipped with large external ears that are served by seventeen muscles, and can prick and swivel these sound receivers to focus on the source of any noise. They can register sounds of 35,000 vibrations per second (compared to 20,000 per second in man and 25,000 per second in the cat), which means that they can detect noises well beyond the range of the human ear. They are also sensitive enough to tell the difference between, for example, two metronomes, one ticking at a hundred, and the other at ninety-six beats per minute. Dogs can also shut off their inner ear so as to filter from the general din those sounds on which they want to concentrate. (This gift makes them ideal guests at cocktail parties!)

Other abilities

Like cats, dogs are very sensitive to vibrations and will give warning of earth tremors some considerable time, and occasionally even days, before humans are aware of any movement. The curious thing is that dogs react like this only to the imminence of true earthquakes; somehow they can tell the difference between advance tremors of the real thing and the 150,000 other harmless vibrations of the earth's crust that occur each year and do not alarm them.

The dog is equipped with one efficient weapons system -- its teeth. The powerful jaw muscles provide a hefty bite if required. A 44lb (20kg) mongrel has been found to exert a bite of 363lb (165kg) pressure. The average human adult can gnaw no harder than 45-65lb (20-29kg), and the strongest of men under special training can only manage 160lb (73kg).

Finally, what about extrasensory perception in dogs? Repeated testing under apparently stringent conditions has produced evidence to suggest that certain canines possess psychic/ telepathic abilities: what is usually referred to in humans as a "sixth sense". This is how your dog knows you're going for a walk even before you've decided yourself!

Behavior and Intelligence

Dogs stand higher in the IQ league than cats, canaries, or ponies. They are excellent learners with good powers of association. As social animals they are adept at interpreting subtle signals conveyed by other individuals -- canine or human. Together, these traits enable the dog to "understand" people and to establish friendships with them.

Scent and visual signaling

Signaling plays an important part in a dog's life. Many messages involve smell: dogs mark territory by frequent urination, and by scratching the ground to leave scent from sweat glands in the paws. They also roll in grass and more pungent substances such as manure in order to enhance (to a dog's nose at least) their body odor.

Visual signaling by body language is highly developed too. A varied repertoire of body postures, facial expressions, and tail signals transmits information that other dogs, other animals, and humans can interpret. There is also a wide range of sound signals that includes aggressive growls and snarls, whines, howls, "yips" (from hounds while hunting), and a variety of barks.

The importance of play

Puppies love to play, and their play is more than just joie de vivre. Its purpose can be traced back to their wild relatives. Not only is it a substitute for hunting, prompted by the instinct of the pack-hunter, but it also provides valuable physical exercise for the growing animal. The puppy learns about the world as it investigates everything with its senses, and meanwhile it develops the social skills so important to such a gregarious species. Even more than kittens, which inherit a self-reliant, rather solitary way of life, puppies need lots of contact with their peers and human friends in order to grow up into well-adjusted adults. Puppies deprived of contact with other dogs during the crucial period from three to ten weeks, when they are at their most playful, will not develop correct social responses. What is lost during this vital period cannot be instilled later. Such individuals become neurotic, with a tendency to be antisocial and unable to form normal relationships with other dogs.

For adult dogs, play is mainly fun and exercise, although in their wild cousins it may also serve to remind each animal of its position in the social pecking order. This helps to reduce the risk of serious fighting.

Antisocial behavior

Understandably with such a complex and intelligent species, things do go wrong, and dogs can sometimes present behavioral, psychological problems. These can range from the "problem puppy" that will not house-train, to serious biters, barkers, leg-mounters, and dogs with specific phobias.

Very rarely is a dog truly psychotic -- behaving totally irrationally. In almost every case, its behavior can be explained by an examination of the fundamental nature of Canis familiaris. The fact that the dog is descended from social hunting animals, and an individual has had a deficient upbringing, usually explains everything.

The good owner must study and understand his or her dog's essential character. If antisocial behavior does arise, the vet should be consulted, and then perhaps an animal behaviorist or "dog psychologist".

Copyright © 1990 David Taylor