Complete Guide : Snake Anatomy and Physiology

Snake anatomy -

Complete Guide : Snake Anatomy and Physiology

Hi, Snake fan! 🐍

The doctors always say, "If you don't know what is normal, you will never know what is abnormal" and that is much more true for anatomy, a very important branch of medicine. Veterinarians (animal doctors) need to know anatomy to perform a physical examination, interpret x-rays, and operate. If you have a snake, you must know the anatomy of your pet to be able to detect any changes. Get ready, this species is fascinating in its whole even in its anatomy. We have countless species of snakes: Sea-snakes, Coral-snake, Rat-Snake, Viper, Milk Snake, Brown Snake, Eastern diamondback rattlesnake, 
King-cobra, Green-snake, Corn-snake, Boa-constrictor.

1) Anatomy of the Snake

snake anatomy


Because snakes are long, it is possible to divide their main anatomical parts into sections.

A. The Different Organs of the Snake

If you put the snake straight on a table, you put the skull on the left and the end on the other side; going from left to right, by doing this you can see better the separation between the organs, the first 25% is composed of the main organs: the head, the esophagus, and the trachea, and the heart ❤.

If we continue on the same logic there is a part between 26% and 50% composed of the lungs, liver, and stomach.

The venom is regulated by itself and therefore it escapes central (neural) control. Researchers have discovered baroreceptors in the gland that regulate the amount of venom production, and this regulation is made possible by the pressure in this accessory gland. Not all venom components are produced at the same rate. There is a big difference between fresh venom and mature venom. Chemical reactions must occur within a few days 🐍.

The connection between the fangs and the gland is made by a channel passing through an accessory gland (yes there is a lot of glands), which serves to transport the poison. As this gland is not controlled by smooth muscle but by the striated muscle (the muscle you can control), the amount of venom ejected during the bite is regulated voluntarily by the snake. The secretions of the accessory gland are harmless 💀 (they have a foamy appearance) but it is in contact with the venom that it reinforces the poison.

The fangs have a conical shape with a specific curvature, being hollow to allow the circulation of the venom during a bite. The fangs can be replaced when they are damaged or lost. There begin the envenomation. Some snakes can spit venom. This is an ability that allows them to be more effective when attacking prey.


snake fangs


You should know that like any other species of animals there are differences between each type of snake, sea snakes 🌊 their tail is flattened, rattlesnakes have pits but also other changes. The administration of venom can be different in each species too.

Finally, we have the third section consisting of the remaining 51 to 75% of the reptile's body. So we have another part of the organs the gallbladder, spleen, and pancreas (or spleen pancreas, depending on the species). The gonads can be found by following this triad of organs.

In the last quarter, the remaining 25% of the reptile, will be found the small intestine, large intestine, cecum, kidneys (just in front of the left), and cloaca.

If you have read this whole section it means you are passionate and that you would be a good herpetologist. 🦎

B. Why snakes have no legs (Apod)


snake no legs


If we look at the majority of reptiles, they have 4 legs except for the snake, which does not have a pelvic girdle (support of the back legs) nor a thoracic girdle (shoulder bones). The scales of the snakes cover their entire body to protect them from injury. They can be smooth and shiny (python) or rough and dull (hognose snake). The skin is composed of two layers, the first (thinnest) is called the epidermis and is the layer that the snake changes when it loses its skin. The second layer is much thicker called dermis it is filled with chromatophores giving each snake its specific color. Nature is beautiful!

2) Snake scales

The scales have a unique composition (keratin) coming from the epidermis. As the snake grows (throughout its life) this epidermis will slowly peel off. Mythology says that a certain snake fossilized after its molt, this story has inspired many authors.


A. Molting of the Snake 

What's molting? New scales grow underneath the old outer scales. Eventually, the outer layer comes off like a sock. If this step is done in a fragile way then there is an underlying problem. We can, therefore, blame the humidity, the ambient temperature, the quality of the terrarium. This is an important point in the health of the snake.

The scales are attached by soft skin, usually invisible from the outside, which folds inward between each adjacent scale. The scales cannot stretch, but when a snake eats a large meal, the folds of skin are stretched to the surface. For this, you can discover our blog about the loss of snakeskin.

B. The Different Types of Snake Scales


Snake Scales

We have two main types of scales, they can be juxtaposed or overlapping. The bottom of the snake is often covered with very wide and short scales, they are called scutes. They are here to form the belly of the snake and protect the moving part of the snake.

Snakes cannot close their eyes (even though Snakes have two eyes 👀) because they have no eyelids. But they have a very thin transparent scale protecting the eyeball. Important info: when the snake loses its skin it also loses this scale. Herpetologists call this phenomenon "in the blue". Owners often panic about this situation, even though it is completely normal.

3) Anatomy of the Snake Head

A snakehead contains the eyes, nostrils, mouth (and internal structures), brain 🧠 , and a special sensory structure called the vomeronasal or Jacobson's organ.


snake head anatomy

A. Jacobson's Organ


Jacobson's Organ

The main olfactory organ of reptiles, it is used to decode odorous molecules in the air. Its two openings are located on the palate of the oral cavity. These molecules are then analyzed by the reptile's nervous system when they shake their tongue 👅. Essentially, this is how the snake smells.

B. Tooth of the Snake


Snake Tooth

Snake teeth attach to the upper and lower jawbones. Non-venomous snakes have four rows of upper teeth (two attached to the jawbones (outer) and two rows attached to the inner bones (palatine and pterygoid)). Only two rows are found on the lower jaw; one is attached to each mandible.

Venomous snakes will nibble these teeth (maxillae) with fangs 🦷. These can be in the front part of the mouth (rattlesnake) or the back (owl). As we have said, the teeth are used for grasping, but also thanks to the curvature of these fangs then the only finality for the prey will be the stomach of the snake. 🐍

C. Snake Ears

Unlike humans, the snake does not have an external ear, but it does have an internal ear to listen to frequencies between 100 and 700 hertz (a young person with normal hearing can hear frequencies between about 20 and 20,000 hertz). The internal organ of this reptile also allows it to detect ground movement, static position, and waves propagating in the ground 👂🏻.

The labial pits contain a series of openings throughout the jaw to detect heat. These sensory dimples help the snakes acquire prey and warn them of possible predators nearby.

4) How does the Snake Breathe?


how the snake breathes


The opening at the mouth of the snakes is called the glottis, which opens over the trachea and windpipe. The trachea will always be closed  (forming a vertical slit) except when breathing. A small piece of cartilage just inside the glottis vibrates as the snake expels carbon dioxide from its lungs. This is why this reptile whistles. If the snake eats, it can move the glottis to the side of the mouth and thus allow optimal breathing when eating large prey. 🐀

Snakes breathe primarily by contracting the muscles between their ribs. Unlike mammals, they do not have a diaphragm, the large smooth muscle responsible for breathing in and out between the chest and abdomen. Inhalation is an active process (a contraction of the muscles), while exhalation is passive (the muscles relax).

The snake's lung is composed of two parts, an upper part near the skull allowing the exchange of oxygen. But also another part closer to the tail resembling an air sac (balloon), there is no exchange in this area.

5) Venomous Snake


venomous snake

We have huge and very dangerous snakes (toxicity) but the ways of killing are very different, there is the constriction but also the venom. We will focus on the second one on this blog. Everybody knows what this venom injection is for: To kill prey. The anatomy of venomous snakes (snake venom) is very varied, but some aspects are universal. All snakes have similar systems of venom delivery devices, including venom glands, a duct with an accessory gland, and fangs for delivery venin ☠.

The glands are where the venom is produced and consist of three main types of cells: basal cells, mitochondrial-rich conical cells, and secretory cells, which produce the venom. Be careful with snake bites or just walk with an antidote or antivenom (Medical attention).


6) Digestion in Snakes

Snakes are carnivorous animals, so their diet is composed of Rodents Reptiles, Amphibians, Lizards, Insects. You should know that for the majority of snakes, the mouth only serves as a hook for the prey 🥩, chewing is nonexistent in this kind of animals, it rather uses the mobility of its head to move the prey deeper into the cave until it swallows it completely.

As far as saliva is concerned, unlike the saliva that humans secrete, it has no digestive role, but it lubricates the food, allowing it to pass into the esophagus and stomach. Also, the esophagus is composed of certain longitudinal folds allowing it to receive a large quantity of food.

Then, the tube-shaped stomach ends in a valve called a pylorus which controls the arrival of the food bolus into the next stage of the digestive tract: the duodenum. The duodenum is located just after the end of the long dark brown spindle-shaped liver. The type of species also plays a very important role: Black Mamba, Tiger-snake, Ball python, Watersnake, Green anaconda, Reticulated Python, Burmese python, Massasauga rattlesnake, BullsnakeEastern brown snake, Indigo-snake.

snake rat eating

There, you are now a specialist in the anatomy of the Snake!

Are you a fan of snakes? So are we! The Vipers House is above all a place to share your passion for snakes. It's a passion that has allowed us to create countless pieces of 💍 jewelry and exceptional clothes in our workshops.

Snake Ring Silver

Snake enthusiasts, terrarium enthusiasts or those looking for a unique style, you've come to the right place. 🐍

Come and discover other diverse and varied subjects about snakes by visiting our blog.

snake ring silver


Here are some pictures of snakes so that you can contemplate the anatomy of these animals:

cobra greensnake head tonguecobra head yellowsnake fangscorned snake eatvenom python headgreen mambagreen mamba attackanaconda attackpython dangerous venom fang

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