It has been suggested that the most significant benefit would have been the use of dogs' robust sense of smell to assist with the hunt. The relationship between the presence of a dog and success in the hunt is often mentioned as a primary reason for the domestication of the wolf, and a 2004 study of hunter groups with and without a dog gives quantitative support to the hypothesis that the benefits of cooperative hunting was an important factor in wolf domestication.
The role of the dog in Chinese mythology includes a position as one of the twelve animals which cyclically represent years (the zodiacal dog). Three of the 88 constellations in western astronomy also represent dogs: Canis Major (the Great Dog, whose brightest star, Sirius, is also called the Dog Star), Canis Minor (the Little Dog), and Canes Venatici (the Hunting Dogs).
In a study of seven breeds of dogs (Bernese mountain dog, basset hound, Cairn terrier, Epagneul Breton, German Shepherd dog, Leonberger, and West Highland white terrier) it was found that inbreeding decreases litter size and survival. Another analysis of data on 42,855 dachshund litters found that as the inbreeding coefficient increased, litter size decreased and the percentage of stillborn puppies increased, thus indicating inbreeding depression. In a study of boxer litters, 22% of puppies died before reaching 7 weeks of age. Stillbirth was the most frequent cause of death, followed by infection. Mortality due to infection increased significantly with increases in inbreeding.
In addition, people with pet dogs took considerably more physical exercise than those with cats and those without pets. The results provide evidence that keeping pets may have positive effects on human health and behaviour, and that for guardians of dogs these effects are relatively long-term. Pet guardianship has also been associated with increased coronary artery disease survival, with human guardians being significantly less likely to die within one year of an acute myocardial infarction than those who did not own dogs.
Brush the dog's teeth. Ideally, brushing your dog’s teeth every day with dog toothpaste is the route to healthy teeth and gums. Use dog toothpaste instead of human products, so you don't poison your dog with fluoride. If there is any chance that you may get bitten by your dog, do NOT attempt to brush your pet’s teeth. At any point, if the dog gets overwhelmed, give him a break to calm down.
According to the Humane Society of the United States, 3–4 million dogs and cats are euthanized each year in the United States and many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or castrating dogs helps keep overpopulation down. Local humane societies, SPCAs, and other animal protection organizations urge people to neuter their pets and to adopt animals from shelters instead of purchasing them.
Clean your dog's ears. It's normal for a clean ear to have some wax in it, but there shouldn't be any particular smell to it. To clean your dog's ears, apply some ear cleaning solution (bought at a pet supply store) to a cotton round. Not too much or it will drip into the ear while wiping. Wipe dirt and wax away from the inner ear, but don't rub vigorously, as this might cause sores. Don't push too far into the ear, either. If your dog has drop ears like a bassett hound, wipe the inside of the ear flag as dirt collects there as well. The groomers rule of thumb is to clean only what you can see.
Long fur on the paws acts as a trap for grass seeds, grit, or even ice, so regular trimming is advisable. Use a pair of curved scissors with rounded tips. Work on one toe at a time and twirl the fur growing between two toes between your finger and thumb, and then snip the hair off at the base. Be careful never to pull on the fur, which elevates the skin and makes cutting it more likely. If you cannot see where the skin ends and the fur starts, then slide a comb through the fur at skin level, and using the scissors cut on the safe side of the comb. Repeat for each toe on each paw.
Wolves, and their dog descendants, likely derived significant benefits from living in human camps – more safety, more reliable food, lesser caloric needs, and more chance to breed. They would have benefited from humans' upright gait that gives them larger range over which to see potential predators and prey, as well as better color vision that, at least by day, gives humans better visual discrimination. Camp dogs would also have benefited from human tool use, as in bringing down larger prey and controlling fire for a range of purposes.
Toxocara canis (dog roundworm) eggs in dog feces can cause toxocariasis. In the United States, about 10,000 cases of Toxocara infection are reported in humans each year, and almost 14% of the U.S. population is infected. In Great Britain, 24% of soil samples taken from public parks contained T. canis eggs.[failed verification] Untreated toxocariasis can cause retinal damage and decreased vision. Dog feces can also contain hookworms that cause cutaneous larva migrans in humans.
Raised grooming tables and bath tubs keep you from bending your back and hurting yourself. Any table or sturdy surface could serve as a makeshift grooming table, but always have a non-skid surface for the dog to stand on. That means no wheels on the table. Hardware stores usually carry rubber-backed or rubber runners sold by the yard that you can cut to size of any surface.
The dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such as hunting, herding, pulling loads, protection, assisting police and military, companionship, and, more recently, aiding handicapped individuals. This influence on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogs are also a source of meat.
Clip the dog's nails. If left untrimmed, a dog's nails can curl under into the paw pads or twist toes in a way that causes joint damage. To keep your dog's nails short, clip them regularly, depending on how fast his nails grow. If you can hear his nails on the ground when he walks, that means his nails are touching the ground, and are too long. 
Rinse your dog thoroughly. As long as you see dirt or soap bubbles in the water coming off of an area, keep rinsing. You can use the same method you used to soak the dog's coat before shampooing. If your dog is too afraid of running water or the bath in general and can't be done on your own, there are veterinarians who can give proper sedation, not too much, to allow you to groom in a couple of hours or can groom the dog themselves. Touch the dog all over to feel for any shampoo especially the chest area and in between the legs they are hard to get. To test it, rub the fur in between you fingers and pull softly, if it feels squeaky then it's clean.
Don't overdo bathing. Once every 6 to 8 weeks is typically enough. Professional grooming services are recommended once every 4 to 6 weeks for long haired breeds. Bathing too often can dry out the skin by removing the natural oils. Waterless shampoo can be used between baths to clean feet and other areas. Spot spray directly and sponge off with a damp sponge. Use a hypoallergenic or mild oatmeal shampoo designed for dogs for general bathing. If your pet has a particular skin condition, try hypoallergenic scent free shampoo before the vet. If the condition persists, a medicated shampoo from your veterinarian may be in order. Consult your veterinarian if there are concerns about your pet’s skin.
Typically, you should tip your dog groomer 15 to 20 percent of the service total to show your appreciation for a good job. Tips should be whatever you can afford and are a token of you gratefulness. It's quite common for your groomer to give you extra services at no charge, such as teeth brushing or nail trimming. Keep all this in mind when considering how much to tip. Additionally, there are certain circumstances when you should the tip the groomer a bit more.
"The most widespread form of interspecies bonding occurs between humans and dogs" and the keeping of dogs as companions, particularly by elites, has a long history. (As a possible example, at the Natufian culture site of Ain Mallaha in Israel, dated to 12,000 BC, the remains of an elderly human and a four-to-five-month-old puppy were found buried together). However, pet dog populations grew significantly after World War II as suburbanization increased. In the 1950s and 1960s, dogs were kept outside more often than they tend to be today (using the expression "in the doghouse" to describe exclusion from the group signifies the distance between the doghouse and the home) and were still primarily functional, acting as a guard, children's playmate, or walking companion. From the 1980s, there have been changes in the role of the pet dog, such as the increased role of dogs in the emotional support of their human guardians. People and dogs have become increasingly integrated and implicated in each other's lives, to the point where pet dogs actively shape the way a family and home are experienced.
Dogs are highly variable in height and weight. The smallest known adult dog was a Yorkshire Terrier, that stood only 6.3 cm (2.5 in) at the shoulder, 9.5 cm (3.7 in) in length along the head-and-body, and weighed only 113 grams (4.0 oz). The largest known dog was an English Mastiff which weighed 155.6 kg (343 lb) and was 250 cm (98 in) from the snout to the tail. The tallest dog is a Great Dane that stands 106.7 cm (42.0 in) at the shoulder.
The practice of using dogs and other animals as a part of therapy dates back to the late 18th century, when animals were introduced into mental institutions to help socialize patients with mental disorders. Animal-assisted intervention research has shown that animal-assisted therapy with a dog can increase social behaviors, such as smiling and laughing, among people with Alzheimer's disease. One study demonstrated that children with ADHD and conduct disorders who participated in an education program with dogs and other animals showed increased attendance, increased knowledge and skill objectives, and decreased antisocial and violent behavior compared with those who were not in an animal-assisted program.
Take extra care with dark-nailed dogs not to clip to the quick (blood vessel). Go slowly, and only take a little bit off at a time. Dremeling is much safer and easier to avoid hitting the quick, as it shaves only a little bit at a time. Use a cordless pet-safe Dremel tool, as the corded ones will not stop turning if they catch hair. Don't dremel for too long as it will burn the nail and prolong the trimming process for the dog which causes more stress. The best recommended process is trim first then dremel to shorten a little bit and round out the nail do it's not sharp.