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.
