Snakes are some of the most mysterious creatures on Earth. With their long, limbless bodies, unique forms of locomotion, and lack of external ear openings, snakes possess many anatomical traits that set them apart from other animals.
If you’re short on time, here’s a quick answer to your question: Yes, snakes do have tails. A snake’s tail extends from the end of its body and contains vertebrae, muscles, and scales like the rest of the snake’s body.
In this approximately 3000 word article, we’ll take an in-depth look at snake anatomy, examining the form and function of the tail and other key body parts of serpents. We’ll look at how the snake tail assists with balance, locomotion, courtship, and defense.
We’ll also overview snake skeletal and muscular systems, comparing anatomy across different snake taxa. By the end, you’ll have a detailed understanding of the anatomy of these unique reptiles.
Defining the Snake Tail
Distal Portion of the Body
The tail of a snake makes up the distal or rear portion of its elongated, limbless body. Located posterior to the cloaca, the tail extends beyond the snake’s anus and reproductive organs to the very tip of its body.
Anatomically, a snake’s tail contains vertebrae and is covered in scales, just like the rest of its body.
In some snake species like rattlesnakes and vipers, the tail may have specialized scales, bones, or other structures that serve additional functions beyond locomotion. For example, rattlesnakes have keratin segments at the end of their tails that vibrate together to produce their iconic warning rattle sound.
Contains Vertebrae
Inside a snake’s tail are small vertebral bones called caudal vertebrae that give the tail flexibility and allow snakes to move through their environments. The number of caudal vertebrae can vary significantly between species, from as few as 10 to over 270.
For example, pythons may have between 60-90 caudal vertebrae in their tails while some species of rat snakes have over 270. Generally, snakes specialized for climbing and arboreal movement tend to have more caudal vertebrae which gives their tails extra gripping power and prehensility.
Covered in Scales
The snake’s tail, like the rest of its body, is covered in protective scales. These scales on the underside of the tail are called subcaudals. Their function is to aid snakes in locomotion by gripping surfaces as snakes push off against them to generate thrust.
| Snake species with higher subcaudal scale counts, like racers and rat snakes, tend to be faster moving and more active predators. | Slower moving snakes that rely more on ambush hunting like pythons and boas have lower subcaudal scale numbers and shorter tails. |
The scales may be smooth and rounded for burrowing species, elongated and ridged for climbers, or keeled (with a raised ridge) for species that need extra grip. Additionally, male snakes tend to have longer tails and higher subcaudal scale counts than females within the same species.
Key Functions of the Snake Tail
Balance and Stability
A snake’s tail plays a vital role in balance and stability. Snakes lack limbs and ears, so their tail compensates by acting as a counterbalance when they move. This gives them agility to climb branches, swim, and make quick turns while hunting prey or fleeing predators.
The tail acts as a “fifth limb” of sorts – redistribute their weight to maintain equilibrium. Snakes rely on their muscular and prehensile tails to anchor themselves. Some species like green tree pythons have prehensile tails to grip branches.
The tail wraps around objects, giving stability for the snake to hold fixed positions.
Aids in Locomotion
In concert with the rest of their flexible spine, the tail provides thrust to propel snakes forward. Muscles in the tail contract and relax to push against surfaces, aiding movement. This helps snakes swim through water, slide across land, and climb up various structures and vegetation.
Aquatic snakes like sea snakes rely heavily on tail locomotion to swiftly maneuver through water. Species adapted to trees and branches, like emerald tree boas, use their tail to launch themselves from branch to branch. The tail works in sync with the rest of their body to give motion.
Used in Courtship and Defense
Snakes use their tails to communicate in courtships and territorial displays. When attempting to mate, male snakes may rub their tails along the female’s body. Some species “wrestle” by coiling and pressing their tails together.
Rattlesnakes are most famous for tail signaling. The distinct sections of a rattlesnake’s tail vibrate rapidly to create their iconic warning sound when threatened. Other snakes may coil, wiggle, or lash out with their tails when defending themselves or their territory.
So in short, a snake’s tail allows balance while climbing, swimming, and moving stealthily, propels them forward to hunt prey and escape predators, and communicates messages to potential mates and rivals.
Skeletal Anatomy of Snakes
Overview of Vertebral Column
The vertebral column, also called the backbone or spine, is a crucial part of a snake’s skeletal structure. It is composed of numerous vertebrae linked together to provide strength, structure, and flexibility to the snake’s elongated body (Source).
The number of vertebrae differs significantly among species, ranging from around 200-400. Each vertebra has associated ribs for muscle attachment.
There are different types of vertebrae along the spine corresponding to key body sections. The vertebrae toward the head enable movement for striking and subduing prey, while those in the mid-body provide lateral flexibility for winding maneuvers.
The more numerous posterior (back) vertebrae allow for vertical compression and extension to ingest large prey items.
Tail Vertebrae Differ Among Species
Whether or not snakes have an anatomically distinct tail is a topic of debate among herpetologists (snake experts). Many use the term “tail” loosely to refer to the posterior tip of a snake. However, some species do contain unique caudal vertebrae toward the end of their spine.
These have different structural properties compared to other vertebrae.
| Snake Species | Caudal Vertabrae? |
|---|---|
| Rattlesnakes | Yes |
| Rat snakes | No |
Most species with caudal vertebrae tend to be from the viper family. Rattlesnakes provide a prime example, containing around 20-25 vertebrae often fused into a hard rattle segment used for signaling (Source). So in some snakes, tail vertebrae provide unique biological utility.
Other Key Bones
Beyond the vertebral column, snakes contain other specialized bones related to ecological niche and behaviors, including:
- Skull bones – Allow the mouth to open incredibly wide for consuming large prey. Linked by stretchy ligaments.
- Rubbery lower jaw bones – Allow the mouth to further stretch around prey items.
- Various thin rib bones – Provide structure while enabling impressive body flexing and compression.
Muscles of the Snake Tail and Body
Tail Musculature Overview
The tail of a snake contains incredibly complex musculature that allows for their iconic serpentine movements. There are over 150 pairs of muscles in just the tail alone that work together to provide strength, support, and mobility (1).
These muscles are arranged diagonally, horizontally, and vertically to enable side-to-side motions as well as up and down motions of the tail.
Without this strong yet flexible musculature, snakes would not be able to achieve the sinuous, flowing locomotion that allows them to travel smoothly over varied terrain, climb trees, and swim powerfully through water.
The muscles provide tremendous grasping strength to anchor portions of the tail while other sections curve powerfully to drive the snake forward. This gives snakes an irreplaceable evolutionary advantage.
Key Muscle Groups in Locomotion
There are several major muscle groups in a snake’s tail that provide the power and control for their unique movement capabilities (2):
- Lateral intervertebral muscles – Provide sideways bending and compression of vertebrae
- Dorsal and ventral intervertebral muscles – Allow up and down motion of vertebrae
- Intravertebral muscles – Provide strength within each vertebra
- Caudal muscle chains – Long paired muscle groups running the length of the tail on the dorsal and ventral side that enable powerful serpentine propulsion in swimming
These overlapping composite muscle structures give snakes strength, flexibility, support, and precise motor control throughout their tail all the way to the tip. This allows them to perform their signature concertina and serpentine movements smoothly.
Without these specialized muscles, a snake would be unable to achieve such fluid, effortless-looking motion over nearly any kind of terrain. Their strong tail musculature contributes greatly to the iconic snake profile.
Variations in Snake Tails
Rattlesnake Rattle
The rattle is one of the most iconic features found on certain species of venomous pit vipers belonging to the genera Crotalus and Sistrurus. This specialized structure is located at the end of the rattlesnake’s tail and produces the distinctive warning sound for which the snakes are named.
Rattles are composed of interlocked horny segments made of keratin that fit loosely inside one another. When shaken, these segments knock against each other to emit the familiar buzzing sound.
Newborn rattlesnakes have a prebutton – a single segment at the tip of the tail. Each time a rattlesnake sheds its skin, a new segment is added. The number of segments can thus give a rough indication of a particular snake’s age, though they often break off.
Rattles may serve a variety of functions, including warning off potential predators and communicating with other snakes.
| Eastern diamondback rattlesnake | Crotalus adamanteus |
| Western diamondback rattlesnake | Crotalus atrox |
| Sidewinder | Crotalus cerastes |
| Timber rattlesnake | Crotalus horridus |
Sidewinder Horned Tail Tip
The sidewinder rattlesnake has a unique horned scale or spine protruding from the end of its tail. This horn is made up of modified epidermal skin cells and grows proportional to body size. Research suggests that the sidewinder uses its horned tail to anchor itself briefly against the loose desert sand as it moves sideways.
This unusual method of locomotion allows sidewinders to efficiently traverse sandy habitats like the Mojave and Sonoran deserts. As the sidewinder progresses forward, sections of its body lift up and press down to gain friction, while the horned tail provides an additional anchor point to prevent backward slipping.
This variation allows the sidewinder to hunt prey like lizards, rodents, and birds in its extreme desert environment. In fact, the sidewinder is so specially adapted to sandy habitats that it cannot effectively move across hard or rocky surfaces.
Sources:
Conclusion
In summary, snakes do indeed have tails that play important roles in balance, locomotion, courtship, defense, and more. While all snake tails contain vertebrae, muscles, and scales, tail anatomy can vary among species, with unique adaptations like rattles and spike-like scale protrusions.
The snake tail works in concert with the axial musculoskeletal system to enable these legless reptiles to successfully move, hunt, avoid predators, attract mates, and thrive in ecosystems around the world.
We hope this detailed overview has helped shed light on the form and function of the snake tail and other key aspects of serpent anatomy.
