Snakes are serpents and they have more than 3000 species across the globe and almost found everywhere except Antarctica, New Zealand, Ireland and ICeland.
Snakes found in two distinctive types i.e venomous snakes or non-venomous snakes. Out of thousands of snake species, around 600 species are venomous and call significantly injure the humans or can kill.
When it comes to moving from one place to another, snakes can move smoothly over a surface with a twisting or oscillating motion.
Since they don’t have legs, they primarily rely on muscles and scales on their skin.
Snake’s strong muscles help them lift some scales and move along the surface while dragging the scales against the ground.
Since they move in oscillatory motion using scales, do snakes have a backbone?
Do snakes have a spine?
Snakes do have a spine. Since snakes are vertebrates, their spine is made up of 300+ vertebrae. These strong vertebrae unite together to make a long & flexible backbone which helps snakes to protect their organs, provide space for muscle attachment and enhance the oscillatory movement.
When I studied the anatomy of snakes, I found that their body has three major components as follows –
Spine or backbone of the snake is an interesting part to study. On an average, a snake’s spine holds more than 300 vertebrae, while in few species it can go upto 600.
Australian python with scientific name Morelia oenpelliensis is known to have backbone with 600 vertebrae
Since snakes don’t have any limbs, their vertebrae are not names as per the limb girdles associated with them instead they are divided in to the two groups –
- Precaudal [related to the body]
- Caudal [related to the tail]
The part of the spine that runs through the body of the snake is made up of 100 to 450 vertebrae while the tail has 10 to 200 vertebrae.
Each body vertebra has a pair of ribs attached to it except the ones that are just behind the head of the snake. Tail vertebrae do not have rib attachments.
Each vertebra of the snake attaches to the neighbouring vertebra at five points and makes a long spine that provides surface for ribs and muscles to attach.
Here are the primary points where snakes vertebrae attach with each others-
- Centra (Central bodies of vertebral bones)
- Prezygapophyses & Postzygapophyses
- Articulating surfaces
- Zygosphenes & zygantra
Central bodies of bones attach with each other and form a ball-and-socket joint which allows movement between the two bones. Then vertebrae attach with each other at the two projections that arise from the main body of vertebrae i.s. called as prezygapophyses & postzygapophyses
Zygosphene-zygantra joint is one more vertebral bone joint typically found in most reptiles.
Zygosphene is a wedge shape process on the upper part of vertebrae that fits perfectly into the pocket named as zygantrum.
All these connections between the snake’s vertebrae help them in the lateral and vertical rotation and prevent abnormal twisting of the vertebral column providing them rigidity and flexibility for the oscillatory movement.
Like many other vertebrates, spine of snakes shows the spinal discs and elastic ligaments which gives flexibility to the backbones.
Most of the snake’s show the long, posteriorly directed projection on the ventral part of the posterior third vertebrae which is called as the hypapophysis.
Having the hypapophysis is a common characteristic in most of the snake species.
Fun-Fact – In the egg-eating snakes, the hypapophysis is present on the vertebrae which are behind the head and have developed anteriorly pointing tips coated with an enamel-like substance. These projections work as eggshell breakers.
In most snakes, the spine plays an important role for various purposes. Like in the rattlesnake, tail vertebrae are developed to form a “shaker” which is a hollow rattle segment and useful for creating the characteristic sound of rattling.
Function of spine in snakes
Like other vertebrates, the primary function of the spine is to protect the spinal cord, provide rigid support to the body and allow muscle and rib attachment.
Long spine in snakes also helps in maintaining balance and transmitting body weight during the movement.
Overall, snakes have long spines with more than 300 vertebrae. The spine allows snakes to be flexible and elastic enough to get rapid locomotor movement so that they can easily travel along the ground, climb trees and can pass through the underground canals.
Can you break a snake spine?
Yes, a snake’s spine can break if it is pulled and folded in backward direction (dorsally). Though snake has long, flexible spine with more than 300 vertebrae, it is not meant to move or fold in backward direction and