Snakes are animals with a long, narrow and flexible body. They do not have legs, paws, arms, wings or fins. There is only a head, body and tail. But does a snake have a skeleton? Let's find out how the body of these reptiles works.
Features of snakes
Snakes belong to the class of reptiles, the squamous order. They live all over the earth, except for Antarctica, New Zealand, Ireland and some Pacific islands. They are also not found beyond the Arctic Circle and prefer the warm tropics. These animals can live in water, desert, rocky mountains and dense forests.
The body of snakes is elongated and, depending on the species, has a length of several centimeters to 7-8 meters. Their skin is covered with scales, the shape and location of which is not the same and is a species feature.
They have no movable eyelids, outer or middle ear. They hear poorly, but they distinguish vibrations perfectly. Their body is very sensitive to vibrations, and since it is often in direct contact with the ground, the animals feel even slight shaking of the earth's crust.
Vision is not well developed in all snakes. They need it mainly in order to distinguish between movement. Worst of all, representatives of species living underground see. Special receptors for thermal vision help snakes recognize prey. They are located in their facial part under the eyes (in pythons, vipers) or under the nostrils.
Does a snake have a skeleton?
Snakes are predators. Their food is very diverse: small rodents, birds, eggs, insects, amphibians, fish, crustaceans. Large snakes can even bite a leopard or a wild boar. They usually swallow their prey whole, pulling on it like a stocking. From the outside, it may seem that they have absolutely no bones, and the body consists of only muscles.
To understand whether snakes have a skeleton, it is enough to refer to their classification. In biology, they have long been identified as vertebrates, which means that at least this part of the skeleton is present in them. Together with lizards, iguanas, turtles, crocodiles, they belong to reptiles (reptiles), occupying an intermediate link between amphibians and birds.
The structure of the skeleton of a snake has some similarities, but differs in many ways from other members of the class. Unlike amphibians, reptiles have five sections of the spine (cervical, trunk, lumbar, sacral, and caudal).
The cervical region consists of 7-10 movably connected vertebrae, allowing not only to raise and lower, but also to turn the head. The body usually has 16-25 vertebrae, each of which is attached to a pair of ribs. The tail vertebrae (up to 40) decrease in size towards the tip of the tail.
The skull of reptiles is more ossified and hard than that of amphibians. Its axial and visceral sectionsadults grow together. Most representatives have a sternum, pelvis and two limb belts.
Snake skeleton with signatures
The main distinguishing feature of snakes is the absence of front and rear limbs. They move by crawling on the ground, fully relying on the entire body. Limb rudiments in the form of small processes are present in the structure of some species, for example, pythons and boas.
In other snakes, the skeleton consists of a skull, torso, tail and ribs. The body section is greatly elongated and contains much more "details" than other reptiles. So, they have from 140 to 450 vertebrae. They are connected to each other by ligaments and form a very flexible structure that allows the animal to bend in all directions.
The sternum is completely absent in the snake's skeleton. From each vertebra, ribs extend from both sides, which are not connected to each other. This allows you to increase the volume of the body several times when swallowing large food.
The vertebrae and ribs are connected by elastic muscles, with the help of which the snake can even lift the body vertically. In the lower part of the trunk region, the ribs are gradually shortened, and in the tail region they are absent altogether.
Skull
In all snakes, the bones of the brain box are connected movably. The articular, surangular and angular bones of the lower jaw are fused with each other, connected to the dentary by a movable joint. The lower jaw is attached to the upper ligament, which is highly stretchable to swallow large animals.
Sfor the same purpose, the lower jaw itself consists of two bones, which are connected to each other only by a ligament, but not by a bone. In the process of eating prey, the snake alternately moves the left and right parts, pushing the food inside.
Snake skull has a unique structure. If the appearance of the spine and ribs is typical for the entire suborder, then the skull reveals the features of a particular species. For example, in a rattlesnake, the head skeleton has a triangular shape. In pythons, the head is elongated in the shape of an oval and slightly flattened, and the bones are much wider than in the rattlesnake.
Teeth
Teeth are also a hallmark of a species or genus. Their shape and number depend on the lifestyle of the animal. Snakes do not need them to chew, but to bite, capture and hold prey.
Animals swallow their food, but they don't always wait for it to die. To prevent the victim from escaping, the teeth in the snake's mouth are angled and directed inward. This mechanism resembles a fish hook and allows you to firmly bite into prey.
Snake teeth are thin, sharp and are divided into three types: constrictor, or solid, grooved, or grooved, hollow, or tubular. The former are present, as a rule, in non-poisonous species. They are short and numerous. On the upper jaw they are arranged in two rows, and on the lower jaw - in one.
The furrowed teeth are located at the end of the upper jaw. They are longer than solid ones and are equipped with a hole through which poison enters. They are very similar to tubular teeth. They tooneeded to inject poison. They are fixed (with a permanent position) or erectile (pull out of the jaw groove in case of danger).
Snake venom
A large number of snakes are poisonous. They need such a dangerous tool not so much for protection as for immobilizing the victim. Usually two long poisonous teeth stand out clearly in the mouth, but in some species they are hidden in the depths of the mouth.
Poison is produced by special glands located at the temple. Through the channels, they are connected to hollow or embossed teeth and are activated at the right time. Separate representatives of rattlesnakes and vipers can remove their "stings".
The most dangerous to humans are snakes of the genus Taipan. They are common in Australia and New Guinea. Before a vaccine was found, their venom had a 90% mortality rate.
