Dogs are mammals and they are members of a family of animals called canids. We often refer to dogs as canines, sometimes abbreviated as K-9. The canid family includes domestic dogs as well as coyotes, dingoes, foxes, jackals, wolves, and others. They are mostly carnivorous (meaning that they eat meat) but they may also be omnivorous (eating a variety of foods). Wild canids are found on every continent of the world except Antarctica. They live in grasslands, deserts, forests, and on mountains. Wild canids vary in size, but not as much as domestic dogs. The smallest known adult dog was a Yorkshire Terrier that weighed only 4 ounces (113g) and the largest was an English Mastiff which weighed 343 pounds (155.6 kg).
WHAT'S IN A NAME?
The name “dog,” (or something similar to it) like the animal, has been around for thousands of years. A few hundred years ago the name “hound” came to refer to dogs used for hunting. Until dogs are about a year old, they are referred to as “pups” or “puppies.” But not all “dogs” are dogs. For example a prairie dog is not a dog, and neither is a dog fish.
SOCIAL ANIMALS AND SPECIAL PUPPY FOOD
Dogs are naturally social animals. Domestic dogs live with humans. Most wild members of the dog family live in groups called packs, although some may live on their own or in pairs. In a pack the strongest and most experienced animal becomes the leader. The dogs may communicate with scents, by gestures, and by vocal sounds such as barks, growls, and howls. In the wild the pups are born once a year, in litters of 1 to 16, and they may take a year to grow and learn the skills they need to survive. When they begin to eat solid food, their parents may bring back food in their stomachs and vomit it up for the pup to eat.
DOGS DO NOT ALL LOOK ALIKE
Domestic dogs, because of selective breeding, have a wider range of physical and behavior characteristics than any other land mammal. Besides a wide range of difference in sizes, they also have a variety of colors in various patterns, and short or long hair that may be coarse, soft, straight, or curly. Some dogs have a single coat of hair and some have a double coat. The double coat consists of short “down” hair covered by a longer layer of coarse hair. Dogs with double coats do well in cold climates. Dogs often have countershaded hair, meaning that they have a dark coloring on the upper surfaces of the body and a lighter coloring below. Sometimes they will have a stripe or star of white fur on their chest or stomach. Even the body shape and head shape can vary widely. Their tails can be long, short, fluffy, slender, straight, crooked - or no tail at all. Their ears can also be very different. There is much more variation in domestic dogs than in domestic cats.
TOE WALKING
All dogs, like cats, walk on their toes. The bones of their feet are above the ground. Unlike cats, dogs do not have retractable claws. Dogs have an extra claw on the inside of their front legs above the ground level, called a dewclaw. In some breeds the dewclaw may give them extra traction when running, and it can be useful for gripping bones or other items held between the paws.
DOG FOOD
Although dogs are basically carnivores, because they like to eat meat, they can also eat other foods. Unlike cats who cannot digest vegetables, dogs can eat vegetables and grains and still be healthy. They don't require the meat-protein, or the high level of protein that cats need. Even dogs in the wild often eat plants or fruits.
DOG LEARNING
Dogs are capable of learning in more than one way. They learn by what is called reinforcement or conditioning. This means when they are rewarded for a behavior, they repeat that behavior. They can also learn by observation. When they see another dog or a human doing something, they sometimes repeat the action. Puppies learn by observing adult dogs, and they can even learn by imitating human actions. Dogs have been known to flush a toilet after observing a person do it. Dogs can take subtle cues from a human, just by the person looking at the dog and then looking at an object. Dogs will respond to voice and hand signals from humans. Dogs have even been known to practice a little bit of deception by hiding something, perhaps being playful. They are very intelligent in a social way that makes them very popular as pets and useful as service dogs.
TO SEE AND HEAR
Dogs do not have good color vision, like most mammals. Reds and greens look the same to them. However, they are able to distinguish moving objects from great distances. Their eyes are also designed to work well in low-light conditions because of their large pupils, a high density of the light-detecting rods, and a reflective surface behind the retina similar to what a cat has. Long-nosed dogs have a wider field of vision because their eyes are on the sides of their head. Some are able to see in a range of 270 degrees compared to up to 180 degrees for humans. This is almost like being able to see behind your head. Dogs with short noses have eyes facing forward and a more narrow field of vision similar to cats or humans. Dogs are able to hear high-pitched sounds that are beyond the range of human hearing, although not as high as what a cat can hear. Dog whistles which can't be heard by humans are heard clearly by dogs and they will respond to them. Cats can hear them too, but they don't care. Did you ever try to get a cat to come to your whistle?
SUPER SMELLERS
The greatest sense that dogs have is their sense of smell. This is one of the things that makes dogs so useful to humans because they can sniff out hidden illegal drugs or human beings buried in the rubble of a collapsed building. Some breeds of dogs, like bloodhounds, have the sharpest sense of smell. This great sense of smell in dogs is because of the design of their noses and also because of the design of their brains. Dogs are able to detect odors that would have to be about 100 million times stronger for a human to detect them. Also the dog's wet nose makes it possible for it to tell the direction of the air current carrying the odor. However, dogs sometimes seem to enjoy smells that can make a human feel sick. Dogs and humans have very different choices in perfumes.
HEALTH ISSUES
Dogs have sharp teeth in front for slicing flesh and strong molars for cracking bones. They also have strong muscles and a cardiovascular system that gives them great endurance. However, they are subject to many of the diseases that afflict humans, such as arthritis, diabetes, cancer, heart disease, epilepsy, and others. They also are subject to parasites such as heartworms, tapeworms, hookworms, and roundworms as well as fleas, ticks, and mites. Dogs are subject to poisoning by substances which are harmful to humans, but, unlike humans, they can't read the warning labels. For that reason we have to look out for them and keep poisonous substances out of their reach. Dogs can also be poisoned by something which humans often eat – chocolate. Eating even a small amount of chocolate can be fatal to a dog, especially dark chocolate.
MAN'S BEST FRIEND
Domestic dogs have been great companions for humans throughout history. They help to relieve the loneliness of many humans just by being with them. Their natural social skills make them easy to train, fun to play with, and great for companionship. Dogs have also been wonderful working helpers for humans. Dogs have helped in hunting, animal herding, and protection. Dogs have pulled sleds and carts and carried loads. Dogs serve in the police and military. Dogs aid the handicapped, those who are blind or deaf and those who have mobility problems or epilepsy. They have saved the lives of their owners and others by use of their keen senses. Dogs have earned their nickname - “man's best friend.”
DOG'S AND HUMANS - GOOD FOR EACH OTHER
The friendship of dogs and humans has been good for the dogs as well as the humans. Together dogs and humans are often able to hunt better and rescue better than either could do alone. Dog companionship has extended the lives of some humans, and dogs living with humans have longer lifespans than those who live in the wild. Domestic dogs often live until the mid-teens, with the longest verified dog lifespan of 24 years. Dogs are one of the blessings of the world God created.
