What Are Spurs and Why Do Snakes Have Them?

what are spurs and why do snakes have them

Everyone knows that snakes are smooth, limbless reptiles that rely on their teeth, venom, and sheer muscular strength for all of their needs. Would it surprise you to learn that some snakes actually have claw-like appendages called spurs?

What are spurs and why would a snake have them?

Spurs are tiny, curved bones that protrude from the scales on either side of the cloaca of certain snake species. Though some argue that these are vestigial bones retained after the evolution of lost limbs, spurs are actually functional body parts that aid in climbing and mating.

We will take in-depth look at snake spurs including the different species that possess them, what they are made of, how they are used, and much more.

What Snake Species Have Spurs?

Not all snake species have spurs. In fact, most snakes, especially those kept as pets, do not have spurs. Most of the spur-bearing snakes belong to more primitive families of snakes which is what lends credit to the argument of spurs being the remains of retained leg bones.

Let’s take a look at the different kinds of snakes that have spurs.

1.    Boas

Boas are found all over the world from Central and South America to Africa. One of the unique features of this family of snakes is the retention of the claw-like spurs that project out on either side of the cloaca.

In some species, such as the Madagascan boa, they are functionally used for ritual male to male combat to rake against their opponent’s scales, presumably to impress a nearby female during mating season.

While in other boas such as boa constrictors, their use as an aid in climbing trees and clinging to branches has been noted for these arboreal rainforest dwelling reptiles.

2.    Pythons

Like boas, pythons also have spurs that are mainly used for fighting and mating. The hard bony structures almost float within the pelvis, having evolved the need for attachment as an actual limb.

During mating season, spurs become more pronounced since males use them extensively to court females as well as to compete with other males for viable mating opportunities. The Burmese python has a complicated courtship ritual with three different phases and spurs play an important role in stimulating the female to mate with the male.

3.    Slender Blind Snakes

Not quite as large and powerful as the boas and pythons, slender blind snakes are considered primitive snakes. Just like their larger cousins, slender blind snakes also possess cloacal spurs.

However, unlike boas and pythons, the spurs of slender blind snakes don’t usually poke through their skin. Instead, these “leftover” bones simply float beneath the surface of the pelvis. When mating season rolls around, the spurs of males which are a rich metallic color will pop out to help secure a successful courtship.

Some slender blind snakes are avid tunnel diggers and they also use their spurs to grip the sides of the tunnel and push themselves through as they dig.

Do Snakes Have Claws?

When you typically picture a reptile with claws, the curved talons protrude from the ends of digits on a functional limb much like an iguana or an alligator. How can snakes have claws if they don’t have legs?

Some snakes technically do have claws, called spurs, that project from the area where their long ago ancestors had legs. These pelvic claws may not appear as functional as those of other reptiles; however, they do come in handy for climbing trees, digging tunnels, fighting with rivals, and impressing females in courtship.

What Are Snake Spurs Made Of?

Snake spurs are made up of a bony core with an outer cap of keratin. The bones protrude from the pelvis and are thought to be the vestigial remains of limbs from a long ago ancestor. The keratin cap, which is the claw-like portion that extends out from beneath the skin, is similar to our fingernails.

Just like our fingernails and the claws of other animals such as cats and dogs, if the cap is ripped off in courtship or combat, a new one will grow back in its place over time.

Do Both Male and Female Snakes Have Spurs?

Of the snake species that possess spurs, both males and females have cloacal claws. However, since females do not use their spurs during mating and ritualistic fighting like males do, the claws are usually smaller and less pronounced.

The spurs of males are notably larger, more curved, and protrude farther out from the body than those of females. This sexual dimorphism, or physical difference between the sexes, is a minimally invasive way to sex a pet snake like a boa or python that might possess spurs.

Even though females don’t need the spurs for courtship, they can still be helpful for gripping branches in arboreal species and digging tunnels in ground dwelling species.

How Do Snakes Use Spurs?

Although snake spurs are small and may not seem extremely useful, they are far more functional than just the residential limb bones that some people believe them to be. We’ll dive into the different ways snakes use their spurs.

1.    Mating

The most important role of a snake’s spurs, the male’s in particular, is for successful mating. You would think that the spurs would be used to grasp the female in some way to force her to participate in the mating ritual, but the reality is actually very different.

Males use their spurs to scratch up and down the female’s body. This act is evidently pleasing to the female because she becomes receptive to the male snake’s advances and they are able to copulate.

The male repeats this ritualistic stroking several times during the mating process to further ensure that his genes are passed on to the next generation of snakes that will be hatched from the eggs the female lays.

2.    Fighting

Males will also use their spurs to fight with other male snakes in order to gain the favor of a female. Typically, males will wrap their tails around each other and pull against their opponent.

Normally, this action would do little to help win a physical fight; however, with the aid of their spurs, male snakes can do some serious damage. During male to male fighting, the spurs are erected and dig under the scales and into the skin of their opponent.

The loser of such an intense battle may slither away with more than hurt pride since such gaping wounds can be a playground for bacterial infection. The winner of the battle may prove to any female snake observing close by that he is worth mating with since he is strong enough to withstand the fight.

3.    Climbing/Digging

Consequently, spurs are also helpful for getting around. Many of the snake species that possess spurs are arboreal, meaning they live in trees. When you’re a smooth, scaly reptile with no limbs to grip a branch, moving around in the treetops can be difficult. Of course, these also help pet snakes when navigating the human world too.

However, spurs can help boa and pythons grip branches or tree trunks as they make a vertical ascension or wind their way from limb to limb. The curved claws are just big enough to give them a little bit of grasping power as they move along.

On the other hand, some of the slender blind snakes that are also equipped with spurs are tunnel diggers. In a similar fashion to tree dwellers, the spurs of ground snakes can also aid in movement within their habitat.

As the snakes dig their tunnels and slowly inch themselves underground, the spurs can help them push through the narrow openings and grip the tunnel walls for extra assistance.

Do Snakes Shed Their Spurs?

For snakes that have spurs, these cloacal claws are included in the shedding process when the snake goes through ecdysis. Since the spurs are not completely made of bone, the keratin cap on the outside is lost with the rest of the old skin.

Just as the new layer of scales hardens post-shedding, the spurs will remain new, harder keratin caps so that the snake can continue to use them for mating and getting around.

Do Anacondas Have Spurs?

Anacondas are considered primitive snakes like boas and pythons and possess spurs on either side of their cloaca. As in most other species, males tend to have larger and curvier spurs than females due to their use in mating and fighting rituals.

Anacondas are perhaps some of the easiest species to tell the males and females apart because the males will have large spurs while the females will typically be larger in overall size.

Do Corn Snakes Have Spurs?

Corn snakes are a more newly evolved snake species than their primitive boa and python cousins, so they do not have spurs.

Corn snakes have completely lost the vestigial bones and use other means for mating and male to male combat.

If you own a corn snake and notice unfamiliar lumps around the cloaca, do not mistake these for spurs. Most likely, you snake is in need of medical attention so you should contact your vet right away.

Do Ball Pythons Have Spurs?

Just like other python species, ball pythons do have spurs. If you have a mating pair of ball pythons, you will notice that the male’s spurs are longer than the females and that he will use them during to entice the female during their mating ritual.

When your ball python begins its shedding process, make sure that the spurs have been shed along with the rest of the old skin. Any retained part of the skin, including the spur caps, can result in a sick snake.

When handling your ball python, be aware of the spurs. Most likely, they will be retracted unless your snake is a male preparing to mate. They may scratch you up a bit, but you could also pose potential harm to the snake if you accidentally tore one off (think of tearing off your fingernails near the skin, ouch!).

This video provides a great example of how easy it is for a ball python’s spurs to fall off:

Conclusion

Snakes have all kinds of curious and unique adaptations but not all of the best traits are newly evolved. The spurs of primitive snakes may or may not be vestigial limbs (the debate still rages), but one thing is for certain – they are plenty useful.

From fighting for a female’s affection to moving about in the treetops or underground tunnels to tickling females during courtship, the little claws that stick out on either side of the cloacal opening are for more functional than most people realize.

The next time you’re observing your boa or python in his enclosure, check out how he uses his spurs and revel in how amazingly adapted snakes can be!