Dog Anatomy

Dogs grow in various sizes and shapes.

The Greyhound is the ‘Fastest Dog on Earth’ and can run 45 miles per hour for short periods of time.

The Irish Wolfhound is the largest dog standing 28 – 32 inches and weighing between 90 – 150 pounds. Irish Wolfhounds make excellent companions, however, their life expectancy is somewhat shorter than most dogs and is between 6 – 8 years.

The Great Dane is the tallest dog standing 30 – 34 inches and weighing 120 – 200 pounds. These too have a short life expectancy and the average age is under 10 years although some can live 12 – 13 years. The Great Dane originates from Germany.

The Chihuahua is the smallest dog standing at only 5 inches tall and weighing 2 – 6 pounds. Chihuahuas can live until they are 15 years old.

The St. Bernard is the heaviest dog. They are very strong, muscular dogs with powerful heads, however, they are extremely gentle and friendly dogs and very tolerant of children. They stand around 26 – 28 inches and can weigh between 150 – 210 pounds.

The worlds oldest dog was an Australian cattle-dog named Bluey who lived to the age of 29 years and 5 months.

Other breeds range in different sizes and weights between the above.

Below is a diagram of a dogs anatomy:

The coat of a dog varies in colors ranging from all black, brown, beige and white to others being of a mix with light or dark markings and colorations on different parts of their bodies and faces.

Their fur ranges from short, smooth fur to long shaggy fur to soft and fluffy to hard and coarse. The shape of a dog is determined by three structures, head, body and legs.

Short smooth fur Long fluffy fur
Shaggy fur Short soft fur

The shape of these structures vary greatly in the same way as their colors and hair characteristics. The two most common head shapes for a dog are a narrow skull with a long face, such as a German Shepherd and a short skull with a short face, such as a pug dog There are many variations to these shapes in between.

Teeth

Dogs have 42 teeth. Six pairs of sharp incisor teeth are in front of the mouth, flanked by two pairs of large canine (‘dog’) teeth. The other teeth are premolars and molars. The incisors and the canines are very important because the dog bites and tears at its food with these teeth.

Tongue

Dogs have fairly thin tongues which are used mainly for guiding food to the throat, for licking the coat clean, and for perspiration. When a dog is overheated, it cools off by hanging its tongue out and panting. As it pants, the evaporation of perspiration from its tongue cools the animal. The dog also sweats through the pads on its paws and very slighty through its skin.

Ears

Dogs ears either stick up or hang down. Dogs have extremely sensitive hearing and can hear far more high frequencies than human ears. This is why they respond to silent whistles.

Eyes

A dog has three eyelids on each eye, the main upper and lower lids and a third lid hidden between them in the inner corner of the eye. The third eyelid can sweep across the transparent cornea of the eye and clean it like a windshield wiper.

Ribs

A dog has 13 ribs in its chest which wrap around the heart and lungs. Since these organs influence the animals speed and stamina, chest size can be an indication of these traits.

Bones

All dogs have 27 bones from the skull to the point where the tail begins. The number of tailbones, however and therefore the length of the tail, varies from breed to breed.

Dogs, on average, are equipped with about 319 bones, though this number can vary slightly depending on the breed or if the dog has more or fewer toes.

Here are some fascinating tidbits about a dog’s bones:

Tail of Tales: The number of bones in a dog’s tail varies depending on the length of the tail. Some dogs are naturally born with short tails, while others have long, whip-like ones. The tail can have anywhere from 5 to 23 vertebrae!
Paws for Thought: Just like humans have metacarpal (hand) and metatarsal (foot) bones, dogs have analogous bones in their paws. Additionally, dogs have a small bone inside the front leg called the accessory carpal bone, which humans don’t possess.
Head Start: The canine skull is quite diverse, morphing through time due to breeding practices. This has led to the wide variety of head shapes we see in different breeds today, from the elongated snout of a Greyhound to the flattened face of a Pug. But regardless of shape, the skull protects the brain and supports the structures of the face.
Backbone of Movement: Dogs have seven cervical (neck) vertebrae, the same number as humans. However, their backbone is more extended, consisting of 13 thoracic (chest) and 7 lumbar (lower back) vertebrae, leading down to the tailbone.
Dewclaw Mystery: Some dogs have a bone inside their dewclaws, the little “thumb” on the side of their paw, while others don’t. This bone structure can be an essential consideration for those thinking about dewclaw removal.

Limbs

The front legs of a dog are called the ‘forelegs’ and the back legs are called the ‘hindlegs’. On each paw, they have 5 toes, however, one of these toes of called the ‘dewclaw’ and is too high up to be of any use. The paw has cushiony pads for each toe and 2 larger pads further up the paw. Dogs perspire (sweat) through their pads.

Heart

A dogs heart beats between 70 and 120 times per minute, compared to a humans 70 – 80 beats per minute. Dogs take between 10 and 30 breathes every minute. Dogs have a visual range of 250 degrees compared to the human range of 180 degrees. A dogs temperature is between 100.2 and 102.8 degrees Fahrenheit.

Lifespan

The average lifespan of a dog ranges from 12 – 14 years. Each one dog year is equivalent to 7 human years.