As dogs are so anatomically diverse we will instead concentrate mainly on behaviour. I suggest those with dog theriotypes should study the individual anatomy of their theriotype, and fill in the blanks with wolf or similair dog species anatomy.
Most breeds of dogs are at most a few hundred years old, having been artificially selected for particular morphologies and behaviors by people for specific functional roles. Through this selective breeding, the dog has developed into hundreds of varied breeds, and shows more behavioral and morphological variation than any other land mammal. For example, height measured to the withers ranges from 6 inches in the Chihuahua to about 2.5 feet in the Irish Wolfhound; color varies from white through grays (usually called "blue") to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; coats can be short or long, coarse-haired to wool-like, straight, curly, or smooth. It is common for most breeds to shed this coat.
We can make several assumptions when considering dog anatomy in comparison to wolves, as after all the domestic dog (canis lupus familiaris) is a subspecies of gray wolf.
Compared to equally sized wolves, dogs tend to have 20% smaller skulls and 30% smaller brains as well as proportinately smaller teeth. Dogs require fewer calories to function than wolves. It is thought by certain experts that the dog's limp ears are a result of atrophy of the jaw muscles. The skin of domestic dogs tends to be thicker than that of wolves, with some Inuit tribes favoring the former for use as clothing due to its greater resistance to wear and tear in harsh weather.
Dogs and humans lived together in a mutually beneficial relationship for some time. The dogs would have more safety, more reliable food and more chance to mate. They would also benefit from the human ability to use tools to bring down prey.
Humans also benefited from the deal, as the dogs would provide warmth and would alert a camp to the presence of strangers and predators. The most significant benefit however was during hunting, where the dog's keen sense of smell would assist in tracking prey.
It has been noted that the cohabitation of dogs and humans may be one reason for human success as a species.
In later years, dogs were kept as company, house guards or as a playmate for children, although working dogs such as Border Collies were still primarily used for work rather than enjoyment.
Dogs have been bred and used for herding livestock, hunting, rodent control, guarding, detection dogs and sled dogs. Nowadays they are also used as service dogs, in activities such as detecting oncoming epileptic fits, guiding the blind and as therapy for people with psychological disorders or physical disabilities.
In the US there is on average 26 fatalaties from dog attacks a year. 77% of dog bites are from the dog of family or friends, and 50% of attacks occur on the owners property (Mailmen and women are most likely to be bitten).
However, owning or being with a dog can enhance psychological health and physical fitness of people. Dog owners are less likely to be on medication, and less likely to visit the doctors compared to non-dog owners.
In addition, dog owners do considerably more exercise than other people.
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 a person with Alzheimer’s disease’s social behaviours, such as smiling and laughing.
Dogs go through a series of stages of cognitive development. As with humans, the understanding that objects not being actively perceived still remain in existence (called object permanence) is not present at birth. It develops as the young dog learns to interact intentionally with objects around it, at roughly 8 weeks of age.
Puppies learn behaviors quickly by following examples set by experienced dogs. This form of intelligence is not peculiar to those tasks dogs have been bred to perform, but can be generalized to myriad abstract problems. For example, Dachshund puppies that watched an experienced dog pull a cart by tugging on an attached piece of ribbon in order to get a reward from inside the cart learned the task fifteen times faster than those left to solve the problem on their own.
A study found a third of dogs suffered from anxiety when separated from others.
A Border Collie named Chaser has learned the names for 1,022 toys after three years of training, so many that her trainers have had to mark the names of the objects lest they forget themselves.
The dog's visual system has evolved to aid proficient hunting. While a dog's visual acuity is poor, their visual discrimination for moving objects is very high; dogs have been shown to be able to discriminate between humans (e.g., identifying their owner) at a range of between 800 and 900 m, however this range decreases to 500–600 m if the object is stationary.
Dogs can detect a change in movement that exists in a single diopter of space within their eye. Humans, by comparison, require a change of between 10 and 20 diopters to detect movement.
The eyes of different breeds of dogs have different shapes, dimensions, and retina configurations. Many long-nosed breeds have a "visual streak" – a wide foveal region that runs across the width of the retina and gives them a very wide field of excellent vision. Some long-muzzled breeds, in particular, the sighthounds, have a field of vision up to 270° (compared to 180° for humans). Short-nosed breeds, on the other hand, have an "area centralis": a central patch with up to three times the density of nerve endings as the visual streak, giving them detailed sight much more like a human's. Some broad-headed breeds with short noses have a field of vision similar to that of humans.
The frequency range of dog hearing is approximately 40 Hz to 60,000 Hz, which means that dogs can detect sounds far beyond the upper limit of the human auditory spectrum. In addition, dogs have ear mobility, which allows them to rapidly pinpoint the exact location of a sound. Eighteen or more muscles can tilt, rotate, raise, or lower a dog's ear.
Consequently, it has been estimated that dogs, in general, have an olfactory sense ranging from one hundred thousand to one million times more sensitive than a human's. In some dog breeds, such as bloodhounds, the olfactory sense may be up to 100 million times greater than a human's. The wet nose, or rhinarium, is essential for determining the direction of the air current containing the smell. Cold receptors in the skin are sensitive to the cooling of the skin by evaporation of the moisture by air currents.