The Dog

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Note: we are trying to keep all the information general regarding to dogs since  the details of structures, characteristics, behaviors, etc,  vary tremendously from breed to breed

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Physical Anatomy and characteristics

 

Like most predatory mammals, the dog has powerful muscles, a cardiovascular system that supports both sprinting and endurance and teeth for catching, holding, and tearing. The dog's skeleton provides the ability to jump and leap. Their legs can propel them forward rapidly, leaping as necessary to chase and overcome prey. 

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They have small, tight feet, walking on their toes (thus having a digitigrade stance and locomotion). Their rear legs are fairly rigid and sturdy. The front legs are loose and flexible with only muscle attaching them to the torso. 

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The dog's muzzle size will come with the breed. All dogs have a ligament connecting the spinous process of their chest vertebra to the back of the neck bone, which supports the weight of the head without active muscle exertion, thus saving energy. This ligament allows dogs to carry their heads while running long distances, such as while following scent trails with their nose to the ground, without expending much energy. 

Dogs have disconnected shoulder bones (lacking the collar bone of the human skeleton) that allow a greater stride length for running and leaping. They walk on four toes and have vestigial dewclaws on their front legs and occasionally in their rear legs.

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Size

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Dogs are highly variable in height and weight. Their length can go from centimeters to more than 2 meters from the snout to the tail and their weight can go from grams to even more than 100 kilograms. So when searching information about size you should search about the breed you identify with.

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Coat

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Modern dog breeds exhibit a diverse array of fur coats, including dogs without fur, such as the Mexican Hairless Dog. Dog coats can vary in texture, color, and markings.

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Tail

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There are many different shapes of dog tails: straight, straight up, sickle, curled and cork-screw. In some breeds, the tail is traditionally docked to avoid injuries. It can happen that some puppies are born with a short tail or no tail in some breeds. Dogs have a violet gland or supracaudal gland on the dorsal (upper) surface of their tails that can be used of identification with other dogs.

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Senses

Vision

 

Like most mammals, dogs have only two types of cone photoreceptor, making them dichromats. Which means that they can only perceive two range of colours from the light spectrum. Behavioural studies have shown that the dog's visual world consists of yellows, blues and grays, but they have difficulty differentiating red and green making their color vision equivalent to red–green color blindness in humans (deuteranopia).

 Example: When a human perceives an object as "red," this object appears as "yellow" to the dog and the human perception of "green" appears as "white," a shade of gray. 

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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 at a range of between 800 and 900 metres (2,600 and 3,000 ft); and 500–600 metres (1,600–2,000 ft) for stationary objects. 

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As crepuscular hunters, dogs often rely on their vision in low light situations: They have very large pupils, a high density of rods in the fovea, an increased flicker rate, and a tapetum lucidum. The tapetum is a reflective surface behind the retina that reflects light to give the photoreceptors a second chance to catch the photons. In more simpler words: Dogs have a very keen night vision thanks to some structures and characteristics of their visual system.

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Hearing

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The frequency range of dog hearing is different compared to humans, dogs can detect sounds far beyond the upper limit of the human auditory spectrum. 

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Dogs have ear mobility that allows them to rapidly pinpoint the exact location of a sound. muscles can tilt, rotate, raise, or lower a dog's ear. A dog can identify a sound's location much faster than a human can, as well as hear sounds at four times the distance.

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Those with more natural ear shapes, like those of wild canids like the fox, generally hear better than those with the floppier ears of many domesticated species.

 

Smell

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Dogs have roughly forty times more smell-sensitive receptors than humans, ranging from about This is thought to make its sense of smell up to 40 times more sensitive than human's.Dogs' sense of smell also includes the use of the Vomeronasal organ, which is used primarily for social interactions. The dog has mobile nostrils that help it determine the direction of the scent. Unlike humans, the dog does not need to fill up his lungs as he continuously brings the odor into his nose. The dog's nose has a bony structure inside that humans don't have, which allows the air that has been sniffed to pass over a bony shelf and many odor molecules stick to it. The air above this shelf is not washed out when the dog breathes normally, so the scent molecules accumulate in the nasal chambers and the scent builds with intensity, allowing the dog to detect the faintest of odors. The wet nose, is essential for determining the direction of the air current containing the smell.

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Touch

 

The main difference between human and dog touch is the presence of specialized whiskers. They are present above the dog’s eyes, below their jaw, and on their muzzle. They are sophisticated sensing organs. Whiskers are more rigid and embedded much more deeply in the skin than other hairs. They can detect air currents, subtle vibrations, and objects in the dark. They provide an early warning system for objects that might strike the face or eyes, and probably help direct food and objects towards the mouth.

 

Temperature regulation

 

Primarily, dogs regulate their body temperature through panting, and sweating via their paws.

 

Behavior

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Communication Behavior

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Dog communication is about how dogs "speak" to each other. These communication behaviors include eye gaze, facial expression, vocalization, body posture (including movements of bodies and limbs) and gustatory communication (scents, pheromones and taste). 

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Social Behavior

 

-Playing: 

 

 

Play between dogs usually involves several behaviours that are often seen in aggressive encounters, for example, nipping, biting and growling. It is therefore important for the dogs to place these behaviours in the context of play, rather than aggression. Dogs signal their intent to play with a range of behaviours including a "play-bow", "face-pawed" "open-mouthed play face" and postures inviting the other dog to chase the initiator. Similar signals are given throughout the play to maintain the context of the potentially aggressive activities. 

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From a young age, dogs engage in play with one another. Dog play is made up primarily of mock fights. It is believed that this behavior, which is most common in puppies, is training for important behaviors later in life. Play between puppies is not necessarily a 50:50 symmetry of dominant and submissive roles between the individuals; dogs who engage in greater rates of dominant behaviours (e.g. chasing, forcing partners down) at later ages also initiate play at higher rates. This could imply that winning during play becomes more important as puppies mature. 

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Facial mimicry is an automatic response that occurs in less than 1 second in which one person involuntary mimics another person's facial expressions, forming empathy. It has also been found in dogs at play, and play sessions lasted longer when there were facial mimicry signals from one dog to another. 

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-Empathy:

 

Dogs orient towards their owner or a stranger more often when the person is pretending to cry than when they were talking or humming. When someone pretends to cry, dogs can sniff, nuzzle and lick this person. The dogs’ pattern of response is behaviorally consistent with an expression of empathic concern. 

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-Personalities:

 

Several potential personality traits have been identified in dogs, for instance "Playfulness", "Curiosity/Fearlessness, "Chase-proneness", "Sociability and Aggressiveness" and "Shyness–Boldness". There have been identified seven dimensions of canine personality: 

1. Reactivity (approach or avoidance of new objects, increased activity in novel situations)

2. Fearfulness (shaking, avoiding novel situations)

3. Activity

4. Sociability (initiating friendly interactions with people and other dogs)

5. Responsiveness to Training (working with people, learning quickly)

6. Submissiveness

7. Aggression

 

Dog Breed plays an important role in the dog’s personality dimensions,  while the effects of age and sex have not been clearly determined. Dogs personality models can be used for a range of tasks, including guide and working dog selection, finding appropriate families to re-home shelter dogs, or selecting breeding stock. 

 

Communication

 

-Mouth shape:

 

-Mouth relaxed and slightly open; tongue perhaps slightly visible or draped over the lower teeth – this is the sign of a content and relaxed dog. 

-Mouth closed, no teeth or tongue visible. Usually associated with the dog looking in one direction, and the ears and head may lean slightly forward – this shows attention, interest, appraising the situation. 

-Curling or pulling the lips to expose the teeth and perhaps the gums – is a warning signal showing the weapons (teeth), the other party has time to back down, leave or show a pacifying gesture. 

-Mouth elongated as if pulled back, stretching out the mouth opening and therefore showing the rear teeth – shows a submissive dog yielding to the dominant dog's threat. 

-"Smiling" is also recognized as a calming signal.

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-Head position:

 

- A dominant or threatening dog that looks directly at another individual – this is a threat, it is pointing its weapons (muzzle/teeth) at them.

-A dominant dog turning its head to one side away from a submissive dog – this is calming them, indicating that it is not going to attack.

-A less dominant dog approaches a dominant dog with its head down, and only on occasion quickly pointing its muzzle towards the higher-status dog – shows no fight intended. In an alternate interpretation that does not involve dominance and submission, turning the head away is recognized as a calming signal.

 

-Yawn:

 

A dog yawn – as with humans, a dog will yawn when tired to help awaken it. Also, a dog will yawn when under stress, or when being menaced by aggression signals from another dog when it can be used as a pacifying signal but not a submissive signal. Both humans and dogs can defuse an aggressive situation by turning their head away and yawning. It is also recognized as a calming signal.

 

-Licking and Sniffing:

 

-Licking behavior can mean different things depending on the context and should not be simply interpreted as affection. Dogs that are familiar with each other may lick each other's faces in greeting, then they begin to sniff any moist membranes where odors are strongest i.e: mouth, nose, anal regions and urogenital areas. These greetings and identification sniffs may turn to licking as well. For mating behaviors, this is done more vigorously than when greeting each other. Licking can communicate information about dominance, intentions and state of mind, and like the yawn is mainly a pacifying behavior. All pacifying behaviors contain elements of puppy behavior, including licking. Puppies lick themselves and their litter-mates as part of the cleaning process, and it appears to build bonds. Later in life, licking ceases to be a cleaning function and forms a ritualized gesture indicating friendliness. When stressed, a dog might lick the air, its own lips, or drop down and lick its paws or body. Lip-licking and sniffing are also recognized as calming signals.

 

-Ears:

 

-Ears erect or slightly forward – attention or alerted.

-Ears pulled back flat against the head, teeth bared – anxious dog that will defend itself.

-Ears pulled back flat against the head, teeth not bared – submission.

-Ears pulled slightly back and slightly splayed – indecision: uneasy suspicion, may turn quickly to aggression.

-Ears flickering, slightly forward then slightly back or downward – indecision: more submissive or fearful component.

-Ears pulled close to the head to give a "round face" also recognized as a calming signal. 

 

-Eyes:

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-Direct eye-to-eye stare – a threat, expression of dominance, or warning that an attack is about to begin.

-Direct eye-to-eye stare to human at the dinner table, followed by direct stare at food– dog wants some food.

-Eyes turned away to avoid direct eye contact – breaking off eye contact signals submission; it is also recognized as a calming signal.

-Blinking is also recognized as a calming signal. 

 

-Tail:

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-Tail horizontal, pointing away from the dog but not stiff – attention.

-Tail horizontally straight out, stiff, and pointing away from the dog – initial challenge, could lead to aggression.

-Tail up, between the horizontal and vertical position – dominant dog.

-Tail up and slightly curved over back – confident, dominant dog that feels in control.

-Tail held lower than the horizontal but still some distance off from the legs, perhaps with an occasional swishing back and forth – unconcerned, relaxed dog.

-Tail down, near hind legs, legs straight, tail swings back and forth slowly – dog feeling unwell, slightly depressed or in moderate pain.

-Tail down, near hind legs, hind legs bent inwards to lower the body – timidity, apprehension, insecurity.

-Tail tucked between legs – fear, can also be a ritualized pacifying signal to fend off aggression from another dog.

-Tail fast wagging – excitement.

-Slight tail wag, each swing of only a small size – greeting.

-Broad tail wag – friendly.

-Broad tail wag, with wide swings that pull the hips from side to side – special happy greeting for someone special.

-Slow tail wag with tail at half-mast – unsure of what to do next, insecure.

-Tail wagging is also recognized as a calming signal.

 

-Body:

 

-Stiff-legged, upright posture or slow, stiff-legged movement forward – dominant dog.

-Body slightly sloped forward, feet braced – challenge to a dominant dog, conflict may follow.

-Hair bristles on back of shoulders – possible aggression, may also indicate fear and uncertainty.

-Lowering the body or cringing while looking up – submission.

-Muzzle nudge – occurs when a submissive dog gently pushes the muzzle of the dominant dog, showing acceptance.

-Dog sits when approached by another, allowing itself to be sniffed – signals acceptance of dominance but does not signal weakness.

-Dog rolls on side or exposes underbelly and completely breaks off eye contact – extreme pacifying or submission signal.

-Dog sits with one front paw slightly raised – stress, social fear and insecurity.It is also recognized as a calming signal.

-Dog rolls on its back and rubs its shoulders on the ground – contentment.

-Dog crouches with front legs extended, rear body and tail up, facing its playmate directly – classic "play-bow" to commence play. It is also recognized as a calming signal.

 

Auditory Communication

 

Long-distance contact calls are common in Canidae, typically in the form of either barks or howls. The long-distance howls of wolves and coyotes is how dogs communicate.

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By the age of four weeks, the dog has developed the majority of its vocalizations. The dog is the most vocal canid and is unique in its tendency to bark in a myriad of situations. Barking appears to have little more communication functions than excitement, fighting, the presence of a human, or simply because other dogs are barking. Subtler signs such as discreet bodily and facial movements, body odors, whines, yelps, and growls are the main sources of actual communication. The majority of these subtle communication techniques are employed at a close proximity to another, but for long-range communication only barking and howling are employed.

 

-Barks:

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-Barking in rapid strings of 3 or 4 with pauses in between, midrange pitch – alerting call, the dog senses something but not yet defined as a threat.

-Rapid barking, midrange pitch – basic alarm bark.

-Barking still continuously but a bit slower and lower pitch – imminent threat, prepare to defend.

-A prolonged string of barks, with moderate to long intervals between each one – lonely, in need of companionship, often exhibited when confined.

-One or two sharp, short barks of high or midrange pitch – typical greeting sound, usually replaces the alarm bark when visitor is identified as friendly.

-Single sharp short bark, lower midrange pitch – annoyance, used by a mother dog disciplining her puppies or by a dog disturbed from its sleep.

-Single short bark, higher midrange pitch – surprised or startled.

-Stutter bark, midrange pitch – used to initiate play.

-Rising bark – indicates having fun, used during play-fighting or when the owner is about to throw an object. 

 

-Growls:

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-Soft, low-pitched growling that seems to come from the chest – used as a threat by a dominant dog.

-Soft growling that is not so low-pitched and seems more obviously to come from the mouth – stay away

-Low-pitched growl-bark – growl leading to a bark is both a threat and a call for assistance.

-Higher midrange-pitched growl-bark – higher pitch means less confident, frightened but will defend itself.

-Undulating growl, going from midrange to high midrange – dog is terrified, it will either defend itself or run away.

-Noisy growl, medium and higher pitch, with teeth hidden from view – intense concentration, may be found during play-aggression, however you need to look at the whole body language to be sure.

 

-Howls:

 

-Yip-howl – lonely, in need of companionship.

-Howling – indicates the dog is present, or indicating that this is its territory.

-Bark-howl, 2-3 barks followed by a mournful howl – dog is relatively isolated, locked away with no companionship, calling for company or a response from another dog.

-Baying – can be heard during tracking to call pack-mates to the quarry.

 

-Whines and whimpers:

 

Whining and whimpers are short, high pitched sounds designed to bring the listener closer to show either fear or submission on the behalf of the whiner or whimperer. These are also the sounds that puppies make as pacifying and soliciting sounds.

-Soft whining and whimpering – hurting or scared.

-Moan or moan-yodel, lower pitched than whines or whimpers – spontaneous pleasure or excitement.

-Single yelp or high-pitched bark – response to sudden, unexpected pain such as a too-hard play bite.

-Series of yelps – severe fear or pain.

 

-Screaming:

 

A yelp for several seconds in length much like a human child, then repeated – anguish or agony, a call to the pack-mates for help, is rarely heard. 

 

-Panting:

 

Panting is an attempt to regulate body temperature. Excitement can raise the body temperature in both humans and dogs. Although not an intentional communication, if the dog pants rapidly but is not exposed to warm conditions then this signals excitement due to stress. 

 

-Sighs:

 

Sighs are an expression of emotion, usually when the dog is lying down with its head on its paws. When the eyes are half-closed it signals pleasure and contentment. When the eyes are fully open it signals displeasure, something the dog expected has not happened, often associated with the dinner table and the food that the dog expected to share did not happen.