Dogs recovering from anesthesia after getting
sterilized.
INTRODUCTION
Dog, mammal generally considered to be the first
domesticated animal. This trusted work partner and beloved pet learned to live
with humans more than 14,000 years ago. A direct descendant of the wolves that
once roamed Europe, Asia, and North America, the domestic dog belongs to the
dog family, which includes wolves, coyotes, foxes, and jackals. Dog ancestry
has been traced to small, civet-like mammals, called miacis, which had short
legs and a long body and lived approximately 40 million years ago.
The evolving relationship between the domestic dog and
humans has been documented in fossil evidence, artifacts, and records left by
earlier civilizations. Prehistoric dog skeletal remains, excavated from sites
in Denmark, England, Germany, Japan, and China, indicate the early coexistence
of dogs with people. An ancient Persian cemetery, dating to the 5th century BC,
contained thousands of dog skeletons. Their formal burial and the positioning
of the dog remains reveal the esteem in which the ancient Persians held their
dogs. The relationship shared by dogs and humans also is evident in cave
drawings, early pottery, and Asian ivory carvings that depict dogs. A statue of
Anubis, the half dog, half jackal Egyptian god, was discovered inside King
Tutankhamen's tomb, constructed in about 1330 BC.
Literary references to the dog include those found in
the Bible and in the Greek classic the Odyssey by Homer. In 1576 an English
physician and dog fancier, John Caius, wrote a detailed text on dog breeds, Of
English Dogges. Dogs are featured in tapestries that were created in the Middle
Ages (5th century to 15th century), and in the work of many artists, including
17th- and 18th-century European painters Peter Paul Rubens and Thomas
Gainsborough.
Although it is not known how humans and dogs first
learned to coexist, people soon discovered the many ways dogs could enrich
their lives. Dogs have been used to hunt for food, herd animals, guard
livestock and property, destroy rats and other vermin, pull carts and sleds,
perform rescues, and apprehend lawbreakers. They have been used during wartime
as sentinels and message carriers. Today trained dogs are used to alert deaf
people to common household sounds, such as the ringing telephone or doorbell;
guide the blind; or retrieve objects for quadriplegics. Perhaps the most common
of the many roles served by the domestic dog, however, is that of companion. As
animals with strong social tendencies, dogs typically crave close contact with
their owners. And people tend to form loving bonds with dogs. This
companionship often helps to ease the pain and isolation of the elderly or
people whose physical or mental health requires long-term convalescence or
institutionalization.
PHYSICAL
CHARACTERISTICS
Domestic dogs vary widely in appearance, particularly
in size. The Shih Tzu, for example, is 20 to 28 cm (8 to 11 in) in length and
weighs 4 to 7 kg (9 to 15 lb). The Irish wolfhound is at the other end of the
scale, measuring about 71 to 94 cm (about 28 to 37 in) at the shoulder and
weighing up to about 61 kg (about 135 lb). Coat color, length, texture, and
pattern also vary greatly. The muzzle may appear shortened, as in the
Pekingese, or elongated, as in the Doberman pinscher. Limbs are relatively
short in the basset hound and dachshund, but long in the greyhound. Ear shape
and carriage also vary, but these characteristics may be influenced by a dog
owner's decision to crop, or cut, the ears to make them stand up. Some dogs,
notably the chow chow, even have a naturally blue-black tongue.
Despite these differences, all breeds of the domestic
dog are essentially identical in anatomy. The skeleton of the domestic dog has
an average of 321 bones, with variation reflecting differences in the number of
bones in the tail and the presence of a dewclaw, an extra digit on the paw that
not all breeds have. The rib cage consists of 13 pairs of ribs; the spine has 7
cervical vertebrae, 13 thoracic vertebrae, 7 lumbar vertebrae, and 3 sacral
vertebrae. Rear paws have four complete digits and front paws have four or five
digits. Most puppies have 28 temporary teeth, which are replaced with 42
permanent teeth at about six months of age.
Some breed differences evolved to help dogs survive in
their native environment or occupation. For example, dogs that lived and worked
outdoors, such as the Komondor of Hungary, needed a thick, weather-resistant
coat to protect them from the elements and, perhaps, the biting teeth of
predatory animals. Similarly, the Labrador retriever developed an oily coat,
webbed feet, and a rudder-like tail to help it perform better in recovering
downed waterfowl.
Just as distinct physical characteristics became
trademarks in some breeds, unusual sensory abilities characterize others. Most
dogs are able to detect scents and hear high-pitched sounds that are beyond
human perception, but some breeds have especially acute sensory skills. The
bloodhound, for instance, can follow a four-day-old track using its highly
developed sense of smell. Other breeds with a keen sense of smell include the
German shepherd, golden retriever, beagle, and Newfoundland. These dogs have
been trained for such varied duties as detecting hidden drugs, explosives,
termites, and even a decomposing body immersed in deep water.
REPRODUCTION,
BIRTH, AND THE YOUNG
Dogs generally reach sexual maturity at about six
months of age, with small breeds often maturing earlier than large breeds.
Female dogs, or bitches, become sexually receptive to mating during a period
called estrus (also called season or heat), which occurs about twice a year for
6 to 12 days. After a gestation period of about 63 days, an average litter of
three to six puppies is born.
Blind and unable to stand, newborn puppies are
helpless and spend 90 percent of their time sleeping and 10 percent nursing.
Becoming chilled is the greatest danger facing a healthy newborn puppy because
its immature circulatory system cannot sustain an adequate body temperature.
For this reason, newborn puppies tend to stay close to their mother or cuddle
together for warmth. Mothers clean, nurse, and defend their pups until they can
live on their own, but fathers do not involve themselves in the care of the
young.
DOG
BREEDS
Of the more than 300 breeds of dogs that exist
worldwide, 148 are recognized by the American Kennel Club (AKC), the primary
kennel club in the United States. Since its founding in 1884 the AKC registers
purebred dogs-dogs whose parents and ancestors were of the same breed since the
breed was first recognized. More than one million such dogs are registered
annually. Kennel clubs in other countries, such as the Canadian Kennel Club,
the Kennel Club of England, and the Japanese Kennel Club, use their own
standards in recognizing dog breeds.
The AKC organizes the 148 breeds it recognizes into
seven groups, based on physical and temperamental characteristics and the
purpose for which the breed was originally developed. The club classifies
breeds as terrier, working, sporting, hound, herding, toy, and nonsporting.
The terriers often have wiry coats and possess a
feisty personality, which reflects their original use in catching prey such as
foxes, badgers, and rabbits. Working dogs, such as the boxer or Alaskan
Malamute, are muscular, even-tempered, and obedient, a necessary quality in
dogs that serve as working partners with humans. Many of the sporting dogs,
such as pointers and retrievers, are active dogs that respond instinctively
when spotting game.
Hounds such as the beagle are known for their stamina,
acute sense of smell, and baying bark, qualities that are an invaluable aid to
hunters and trackers. Other tireless helpers of humans are herding dogs,
recognized for their innate ability to drive livestock and keep farm animals
from straying. The low-to-the-ground Pembroke or Cardigan Welsh Corgi can drive
a herd of cows many times its size. Toy dogs, on the other hand, are known for
their diminutive size and function as companionable house pets. The papillon,
named for the French word for butterfly because it has ears that resemble
butterfly wings, is a happy, friendly dog, suitable for small living spaces.
The final dog group, nonsporting , includes a wide variety of purebreds that
differ in size, coat, overall appearance, and personality, from the shorthaired
spotted dalmatian to the curly-haired poodle.
DOG
BEHAVIOR
Instinctive behaviors of the domestic dog are
comparable to those of its wild relatives, the wolf, coyote, fox, and jackal.
Unlike trained behaviors, such as being housebroken or responding to human
commands, instinctive behaviors are those that dogs do without being taught and
include vocalizations, body language, and marking. For example, by four weeks
of age, puppies bark, whine, growl, and howl--just like their wild relatives.
Even the African Basenji, known as the barkless dog, yodels when aroused. These
sounds, whether elicited in excitement, fear, territoriality, or pain, are one
way that dogs communicate with one another and with other animals and people.
Dogs also communicate through their use of body
language. Facial expression, ear posture, tail carriage, hackle (hair on back)
display, and body stance signal a dog's state of fear, excitement, aggression,
or submission.
Understanding the meaning behind these signals can be
important. Signs of potential hostility in a dog include bared teeth, flattened
ears, erect tail, stiff legs, and bristling back hair; the dog may also growl
or bark. People observing these behaviors should keep their arms at their sides
and slowly back away, while firmly saying "no." When approaching a strange dog,
first ask the owner if the dog may be touched. Once given permission, hold the
hands low and speak softly. Staring directly at a dog may arouse intimidation
or aggression, so eye contact with strange dogs should be avoided.
Dogs typically mark their territory with urine as part
of the social communication between animals in general and among the species. A
dog may defend the territory by growling, barking, or assuming aggressive body
language.
In addition to these instinctive behaviors, dogs are
capable of learning certain trained behaviors, such as following obedience
commands. The domesticated dog is able and willing to learn appropriate
behaviors and is highly motivated to please its owner, critical factors that
have contributed to the success of the domestic dog as a companion.
CARING FOR A
DOG
The decision to adopt a dog should be made carefully
because it is a serious commitment that can last for several years. Small dogs
may live 12 or more years, although very large dogs typically have a shorter
lifespan, sometimes as brief as 8 years. Before buying a dog, potential owners
should examine their lifestyle, living accommodations, and plans for the dog.
Other decisions should include who, in the case of a family, will care for the
dog and whether the family or individual owner will have enough time,
attention, and money to meet the dog's needs.
For example, a busy family might not have the
necessary time to groom a dog with a thick coat, and some people might be
unwilling to keep up with the frequent vacuuming needed with a breed that sheds
large amounts of hair. Further, a large dog that requires lots of exercise
would not thrive in a small apartment, nor would a tiny dog be safe around very
young children, who may be too rough with these dogs. Potential owners also
should decide which gender dog they prefer and if it will be used for breeding.
Another decision is to determine if the dog will be a show dog, a working dog,
or a pet because this will influence which individual to select. Finally,
anyone who would like to acquire a dog should be sure to budget for its food;
medical expenses, which will cover immunizations, check-ups, and sick visits;
and any kennel care required in the owner's absence.
Many people prefer a purebred dog so that they can
predict how the dog will look and act when fully grown. Most veterinarians and
responsible dog fanciers believe that a private breeder with a good track
record in producing healthy puppies is the best option for choosing purebreds.
To locate a breeder, check the newspaper, visit a dog show, contact a
veterinarian or experienced acquaintance, or call a local kennel club or the
AKC. Visit several breeders and meet each litter's dam (mother) and sire
(father), if possible. Be prepared to ask, and answer, a lot of questions.
Reputable breeders vigorously screen prospective buyers to ensure that their
puppies go to good homes. Other potential owners are satisfied with mixed-breed
dogs, called mongrels or mutts.
Animal shelters and humane societies, veterinarian
offices, and classified advertising are all resources for finding a mixed-breed
that meets the needs of a potential owner.
When adopting a puppy, wait until it is at least eight
weeks of age before separating it from its mother. Although the various breeds,
and dogs in general, have different temperaments, look for a clean puppy that
is happy, outgoing, and alert. A puppy that is excessively shy or thin or that
has obvious health problems, such as discharge from its eyes or nose, is not a
good choice.
A new puppy should be taken to a veterinarian soon
after adoption for a thorough physical examination and to ensure that it is
current on vaccinations. All puppies need a series of immunizations to protect
them against distemper, a viral disease that causes respiratory symptoms and
can affect the nervous system; leptospirosis, a bacterial disease that damages
the liver; hepatitis, a viral disease that also targets the liver; parvovirus,
which harms the intestinal tract; and parainfluenza, which causes respiratory
problems. Immunizations for these five diseases are usually administered in one
vaccination. Dogs also need rabies shots to protect them from this virus, which
is transmitted in the saliva by the bite of an infected animal and attacks the
nervous system. Some owners opt for additional vaccinations against Lyme
disease, a bacterial infection that is transmitted by parasitic deer ticks;
kennel cough, a respiratory disease caused by the bordatella bacteria; and
coronavirus, which targets the intestinal tract.
Most young puppies harbor roundworms, intestinal
parasites that are diagnosed by examining a stool sample. Roundworms rob the
puppy of nutrients, resulting in the puppy's failure to thrive; the parasites
are eliminated with several doses of oral medication. Dogs of all ages should
follow a drug regimen to protect them from another parasite, heartworm, which
damages heart tissue, obstructs blood flow, and often causes death. The
veterinarian should also discuss spaying or neutering (making a dog infertile),
which are essential in nonbreeding dogs to protect their health and reduce the
population of unwanted dogs. This common surgical procedure is usually not done
until a pup is six months old.
Veterinarians recommend that dogs of all ages have a
yearly checkup, including vaccination booster shots and screening for external
and internal parasites. Since dogs cannot communicate their health problems
through words, an annual examination is important for the early detection and
treatment of problems. Owners should be aware of signs of possible illness
requiring veterinary attention, including changes in appetite and behavior.
All puppies and dogs have three daily requirements:
plenty of fresh drinking water, correct amounts of nutritious food, and
adequate exercise for the dog's age, breed, and temperament. An outdoor dog
needs shelter from the elements and plenty of shade during the summer months,
and indoor pets must have regular access to the outdoors for elimination.
Whatever their living arrangements, all dogs require the loving attention of
their owners. Grooming considerations vary from breed to breed. Short-coated
dogs usually need to be brushed once or twice a week, whereas long-haired dogs
may need daily grooming to prevent the coat from matting or tangling. Dogs need
only be bathed when dirty, and the shampoo used should be one that will protect
the coat's natural oils.
Grooming also includes attending to the dog's eyes,
ears, teeth, anal glands, and nails; details of such care, however, should
first be explained by a veterinarian.
TRAINING YOUR
DOG
Training is another vital part of raising a happy and
healthy dog. All dogs should be trained to walk on a leash and be housebroken.
Some people prefer housebreaking a puppy by training it to urinate and defecate
on newspapers, which are laid flat in a small area such as a foyer. However,
crate training, in which a dog is confined to a crate for limited periods, is
more effective because dogs will avoid soiling their own living quarters.
Whichever method is chosen, housebreaking should begin as soon as a puppy comes
home with its new owner, who should provide the puppy with frequent
opportunities to urinate and defecate outside. In general, pups are not
completely housebroken until they are at least 12 weeks old.
Most puppies are ready to begin obedience lessons at
six to eight months of age. The first lessons should be relatively brief, about
10 to 15 minutes a day, and gradually increase to 30 minutes, depending on the
dog's level of concentration. Training is best accomplished with lots of praise
and a stern "no" for corrections. The trainer should always be consistent in
reinforcing good behavior and correcting bad behavior and should never strike a
dog. Many trainers use a leash and chain-link collar, known as a choke collar.
Despite its name, the collar is never meant to choke a dog, but is used to
deliver quick snaps to gain and direct a dog's attention. This training collar
is useful in teaching basic obedience commands, such as sit, stay, heel, come,
and down.
DOG
SHOWS
In the United States, the AKC sponsors 14,000
competitive dog shows and performance events each year. Dog show judges
evaluate a dog's conformation to its breed standard-an official physical
description of the ideal specimen for a particular breed-and compare the dog
with other dogs at the show. Most show dogs are competing for points toward
their championship. At a large dog show, such as the Westminster Kennel Club
show held over two days in New York City each February, a field of thousands of
dogs is progressively thinned to a single Best in Show winner.
A variety of performance events are held that seek to
provide dogs with an opportunity to perform the function for which they were
originally bred. For instance, a saluki, a hound dog, may enter a lure coursing
event to demonstrate its skill at pursuing swift prey. Small terriers may
vocalize and lunge into a tunnel after "quarry" at an earth dog trial.
Bloodhounds may follow a scent laid down by handlers at a tracking test. The
puli, a herding dog, may gather a flock of sheep at a herding trial. Many
performance events offer increasing levels of difficulty that are reflected in
a range of titles. Once earned, these titles are entered into a dog's permanent
AKC record. Whether people choose to enter their dogs in formal competition,
work with them, or simply enjoy their companionship, all dogs thrive on the
bond that is fostered by a caring owner.
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Contributed By: Elizabeth M. Bodner, B.A., Ph.D., D.V.M.Editor, American Kennel
Club Complete Dog Book. Author of American Kennel Club Care in Training.
INTRODUCTION TO
DOGS
Dogs recovering from anesthesia after getting
sterilized.