The most popular pets are cats and dogs. Today, about 400 dog breeds and 42 domestic cat breeds are officially registered. But owners, although they love their pets, often know very little about the anatomy and physiology of dogs and cats. Although the owners do not start to love their pets less from this, it is better to bridge this educational gap.
How anatomically similar are cats and dogs? How many ribs does a chihuahua dog have (in the photo below)? As much as a shepherd? How many ribs do dogs and cats have, and what are the features of their skeleton? You will find answers to these questions in the article.
Our longtime companions
The most ancient archaeological finds of dog bones in human dwellings date back to the Stone Age, when people began to lead a sedentary lifestyle. So, finding the skeleton of a dog in the cave of Palegavra (Iraq) is more than 12 thousand years old.
Domestication of a cat occurred much later. It is believed that cats were tamed in Egypt about 5 thousand years ago. In Central Europe, this happened even later - about 1,200 years ago.
The origin of pets
Both cats and dogs descended from wild ancestors. Wolves were the forerunners of dogs, but a more settled way of life led to significant differences in the anatomy and physiology of dogs from the wild progenitor. And yet, all breeds of dogs have a similar structure.
The ancestors of cats were wild cats. In the process of domestication, they became not so long-legged. And numerous crosses with wild cats of Asia and Europe gave material for breeding long-haired breeds.
general characteristics
Our dogs (Canis lupus familiaris) and domestic cats (Félis silvéstris cátus) - belong to the families of canines and cats of the same class of mammals. All of them are carnivorous predators, actively procuring food. These companion animals live an average of 7 to 14 years. Dog sizes vary greatly depending on the breed. With cats, everything is a little easier - they weigh on average up to 4.5 kilograms and at the withers reach sizes up to 25 centimeters.
These predators carry their babies for about 2 months, feed them milk and sometimes show amazing care for their offspring.
There are many books and manuals on the maintenance, care, nutrition of our pets. In relation to dogs, there are much more such books, which is associated with the development of official dog breeding. One of the best works on the anatomy and physiology of dogs (K. S. Stogov) is contained in all instructions for the preparation and training of service dogs.
Cats did not become official, but people love them no less than that. Existing atlases of anatomy and physiology in pictures of dogs and cats give a full understanding of the similarity of these animals.
Features of the structure of bones
Mammalian bones are composed of 20-25% water, and all other (75-80%) solids include organic components (40%) and inorganic salts (60%). Organic substances are represented by 95% of the protein component - collagen, and of the inorganic substances the most is calcium (99% of the total amount in the body) and up to 30 other elements (phosphorus, magnesium, potassium). Collagen gives the bone elasticity, and salt - strength and hardness.
Osteoblasts and osteoclasts are the main cells of bone tissue. The responsibilities of the former include bone tissue production and collagen synthesis. The latter are responsible for the reverse process - the destruction of bone tissue that is not mineralized enough. These processes are parallel, but at a young age, the reproduction of osteoblasts is more intense than osteoclasts. That is why bones grow and are more elastic. It is in this period that a lack of minerals in food leads to bending of bones or their deformations. An example of this is rickets.
In adulthood, osteoclasts begin to work more intensively, and this leads to bone fragility.
Skeleton - support and protection
The purpose of the passive part of the musculoskeletal system of animals is to provide the skeleton and body shape, to provide a place for skeletal muscle attachment. In cats, the skeleton consists of 244 bones, in dogs - up to 292 units. But there may be other options. This is due to the presence or absence of caudal vertebrae.
The skeleton of cats and dogs, the anatomy and physiology of which are quite similar, is divided into the following departments:
- Skeleton of the head (skull).
- The skeleton of the body (cervical, thoracic, lumbar, sacral and caudal).
- The skeleton of the limbs.
And although there are differences in the structure of departments in cats and dogs, there is also something in common. For example, the number of ribs for a dog and a cat is the same - there are 13 pairs of them, unlike a person. We have 12 pairs of ribs.
The structure of the skeletal system in our pets begins to form in the womb. We will talk about how to prevent defects in the formation of the skeletal system later.
Skull structure
Although outwardly the skull of dogs and cats is different, it has the same structure. It consists of the brain and facial part, paired (frontal, temporal, parietal, maxillary, nasal, palatine, zygomatic, lacrimal) and unpaired (sphenoid, hyoid, pterygoid, vomer, inter-parietal, ethmoid, and occipital) bones.
All bones of the skull, except the mandibular, are connected motionless and provide reliable protection to the brain. The lower jaw is joined by a strong joint.
Depending on the breed of animals, the ratio of the brain and facial sections can vary, as well as the length of the jaws.
Predator teeth
Our affectionate favorites still remain carnivorous predators. And their teeth only confirm this.
In cats and dogs, teeth are interchangeable - milk teeth appear at the age of 2 weeks and are replaced by indigenous ones at 3 months of age.
There are 42 molars in dogs (6 incisors, 2 canines, 8 premolars in each jaw, 4 and 3 molars in the upper and lower jaw, respectively).
Cats have fewer teeth - 12 incisors, 4 canines, 3 premolars on the upper and 2 on the lower jaw and 4 molars. Only 30 teeth on both jaws.
The dental formula of pets is exactly the same as that of their wild ancestors. Although there may be options. For example, a Mexican hairless dog has no incisors at all, there are only 4 fangs and 2 premolars on each jaw.
Body structure
The vertebral column of animals has a similar structure and consists of departments:
- Cervical. It has 7 vertebrae.
- Thoracic. Here are the vertebrae to which the ribs of dogs are attached, how many of them were said above (13).
- Lumbar. There are also 7 vertebrae.
- Sacral. It has 3 vertebrae fused into a single bone.
- Tail. There may be options: 20-23 vertebrae in dogs and up to 26 in cats.
The cervical part of cats is more mobile, which is ensured by the special structure of the first two cervical vertebrae - atlas and epistophea. In dogs, their connection has a lower amplitude of rotation.
Ribs are the bones that form the animal’s chest, protecting the heart and lungs and providing respiratory movements. How many ribs in dogs and cats we already know - 26. These paired bones are attached to the thoracic vertebrae. But not all of them are the same.
Some of them are attached to the sternum (true), and some outline the arc (false). The first nine pairs of ribs in the dog (how many of them you already know) are connected on the sternum, and the remaining 4 pairs are not connected to each other. The structure of the skeleton of cats differs little depending on the breed, but in dogs the differences can be significant.
If you want to make sure once again how many ribs the dogs have, carefully study the picture below.
Limb structure
The peripheral skeleton is the bones of the fore and hind limbs. The general structure of paws in dogs and cats is the same. The forelimbs are formed by the scapula, humerus, radius and ulna, the bones of the hand with the bones of 5 fingers. The hind limbs are formed by the femur, tibia and tibia and bones of the foot with 5 fingers. In addition, the bones of the hind limbs are more powerful and strong.
The fingers of the animals end with claws. For dogs, they serve as protection against damage to the foot, and for cats, the claws of the forelimbs are tools of defense and attack.
The front limbs of cats are also distinguished by the fact that their rotation angle is much larger than that of dogs. Underdeveloped clavicles and the method of attaching the forelimbs to the sternum allow cats to get out of the bottlenecks and turn around where the dog needs help from the owner.
How to protect your pet from bone problems
The cat and dog skeleton begins to form in the second and last third of the mother’s pregnancy, and continues to develop until the animal is puberty. But even after this, the skeleton does not remain constant, many factors can influence the bones.
That is why care for the skeleton of a pet begins with the correct and complete feeding of the mother. A growing body requires a sufficient amount of calcium and phosphorus in the diet. In this case, calcium should be more than phosphorus. With an excess of phosphorus and a lack of calcium, the latter is washed out of the bone tissue and there is a “butcher dog effect” or hyperparathyroidism. Excess calcium also will not bring benefits, it contributes to violations in the formation of cartilage.
It should be remembered that calcium is absorbed only in the presence of vitamin D. As you know, the body produces it under the influence of ultraviolet radiation. But an excess of vitamin can be very dangerous - it leads to kidney damage, indigestion.
Thus, an animal of any age needs a balanced diet that meets the needs of the body.
But there are other factors affecting the formation of the skeleton. So, early castration stops the production of sex hormones, which can cause bone underdevelopment. Long-term use of diuretics, corticosteroids, or antibiotics results in bone loss of calcium, suspension of vitamin K production and bone demineralization.