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Snake Fangs 101

Table of Contents for this Hub Series on Snake Venom

  1. What snakes are venomous/poisonous?
  2. Snake Fangs 101
  3. Front- versus Rear-fanged Snakes
  4. Front- and Rear-fanged Snake Envenomation Systems
  5. Snake Venom Composition and Variability
  6. The Utility of Snake Venom Research
  7. The Expert's Guide to Snakebite

Fangs are Specialized Teeth for Delivering Venom

Accurate side-by-side comparison of a Gaboon Viper front-fang and a Mangrove Snake rear-fang. The circles represent entry/exit points for the venom, with the lines being the venom's path inside (front-fang) or alongside (rear-fang) the fangs.

Accurate side-by-side comparison of a Gaboon Viper front-fang and a Mangrove Snake rear-fang. The circles represent entry/exit points for the venom, with the lines being the venom's path inside (front-fang) or alongside (rear-fang) the fangs.

Double-fangs in a Front-fanged Snake

A Prairie Rattlesnake (Crotalus viridis viridis) that possesses two front-fangs on its left side, with the fang on your right being the functional one (the one on the left was just shed, but is still trapped in the fang sheath).

A Prairie Rattlesnake (Crotalus viridis viridis) that possesses two front-fangs on its left side, with the fang on your right being the functional one (the one on the left was just shed, but is still trapped in the fang sheath).

What is a snake fang?

Before we can describe what front- or rear-fangs mean, we must first define what constitutes a fang. A fang is simply an enlarged, specialized tooth (one of a symmetrical pair of teeth) on the upper, outer row of teeth. Whereas nonvenomous snakes possess homodont dentition (with all teeth possessing the same, fish-tooth-like structure: re-curve, non-hollow, needle-like teeth designed for grasping and holding prey), venomous snakes actually possess heterodont dentition (having a pair of enlarged, specialized fangs in addition to the other teeth).

Fangs are structures that have evolved to provide an effective means of delivering venom into the body tissues of prey, which is why they are said to be absent in nonvenomous snakes. Snake fangs are similar to "normal" teeth in that they are replaced continuously throughout the snake's life. Interestingly, only one set of fangs can be functional (effective at transporting venom) at any given time (due to the physical mechanisms involved; each fang must "lock" into place before becoming "active"). This partially explains the phenomenon of "dry" bites, where a snakebite doesn't involve the injection of venom, because if one or both fangs are damaged and/or are in the process of being replaced, then little to no venom will be injected. The photo on the right, "Fangs are Specialized Teeth for Delivering Venom," illustrates an accurate side-by-side comparison of an average adult (~4' long) Gaboon Viper (Bitis gabonica) front-fang (which is just over an inch long) and an average adult (~6' long) Mangrove Snake (Boiga dendrophila) rear-fang.

Double-fangs in a Rear-fanged Snake

A False Water Cobra (Hydrodynastes gigas) that possesses two rear-fangs on its left side, with the fang on your left being the functional one (the one on the right is still waiting in line to replace the active fang).

A False Water Cobra (Hydrodynastes gigas) that possesses two rear-fangs on its left side, with the fang on your left being the functional one (the one on the right is still waiting in line to replace the active fang).

Closeup of a Grooved Rear-fang

This is a closeup of the rear-fang in the top image, showing the groove along the side of the tooth which channels the venom into the open wound.  This fang was shed from an average (~6' long) adult Mangrove Snake (Boiga dendrophila).

This is a closeup of the rear-fang in the top image, showing the groove along the side of the tooth which channels the venom into the open wound. This fang was shed from an average (~6' long) adult Mangrove Snake (Boiga dendrophila).

Kinds of Snake Fangs

There are a couple of different types of fangs, possessing varying degrees of effectiveness at transporting venom into prey/predators. Fangs can be little more than enlarged teeth, or enlarged with a groove along the side for channeling/directing the flow of venom into an open wound (with the groove being variable in length/depth), or enlarged with a hollow core (like a hypodermic needle). As far as venom transport efficiency is concerned, here are the fang types in order of least efficient to most efficient: enlarged < (enlarged+grooved) < (enlarged+hollow). Whereas rear-fanged snakes possess either enlarged or enlarged/grooved fangs, front-fanged snakes all possess enlarged/hollow fangs.

In addition, rear-fangs very rarely exhibit any degree of mobility, whereas some front-fangs are attached to a rotatable maxilla that is capable of swinging the fangs into an "active," erect position from a folded position at rest. Front-fangs may grow to be over 2" in length, much larger than any rear-fangs, as seen in the above photo ("Fangs are Specialized Teeth for Delivering Venom"). Classifying things further, there are four different types of specific dentition that snakes may have. Viperids, which tend to have enlarged/hollow front-fangs on a short maxilla that is capable of being rotated into an "active" position, have solenoglyphous dentition. Elapids, which tend to have enlarged/hollow front-fangs on a large, immobile maxilla, have proteroglyphous dentition. Venomous colubrids, which tend to have either enlarged or enlarged/grooved rear-fangs at the back of a large, immobile maxilla, have opisthoglyphous dentition. Nonvenomous snakes (including nonvenomous colubrids), which lack fangs, have aglyphous dentition.

You may take the quiz below to help reinforce your understanding of snake fangs before moving on to the next hub, which further explores the differences between front- and rear-fanged snakes. You can also check out the video below, which shows a front-fanged snake envenomating and releasing its prey in order to allow it to succumb to the venom without fear of reprisal. If you would like to learn more about snake fangs, please see the Amazon links below for some useful book resources. If you have further questions about snakes that are not addressed by this article on snake fangs (or any other articles in this Snake Venom hub series), please see my hub on FAQs About Snakes.

Types of Snake Teeth

A simplified diagram showing the basic differences between the kinds of snake teeth by emphasizing relative sizes and presence of specialized venom transport mechanisms (grooves and hollows). The large red dots are entry/exit holes of the front-fang.

A simplified diagram showing the basic differences between the kinds of snake teeth by emphasizing relative sizes and presence of specialized venom transport mechanisms (grooves and hollows). The large red dots are entry/exit holes of the front-fang.

Are you a snake fang expert?

For each question, choose the best answer. The answer key is below.

  1. Nonvenomous snakes generally possess fangs.
    • True
    • False
  2. Fangs evolved as a means of introducing venom into an open wound.
    • True
    • False
  3. Snake fangs are durable teeth that never need replacing.
    • True
    • False
  4. All fangs are enlarged teeth with hollow cores, like hypodermic needles.
    • True
    • False
  5. Front-fangs are more effective at venom transport than rear-fangs.
    • True
    • False
  6. Rear-fanged snakes possess the largest fangs in the world.
    • True
    • False

Answer Key

  1. False
  2. True
  3. False
  4. False
  5. True
  6. False

Front-fanged Snakes are Highly Efficient at Injecting Venom and Often Bite-and-release Prey

Disclaimer

This hub is intended to educate people ranging from snake experts to laymen about the particulars of the different kinds of snake fangs. This information contains generalizations and by no means encompasses all exceptions to the most common "rules" presented here. This information comes from my personal experience/knowledge as well as various primary (journal articles) and secondary (books) literature sources (and can be made available upon request). All pictures and videos, unless specifically noted otherwise, are my property and may not be used in any form, to any degree, without my express permission (please send email inquiries to christopher.j.rex@gmail.com).

I wholly believe feedback can be a useful tool for helping make the world a better place, so I welcome any (positive or negative) that you might feel compelled to offer. But, before actually leaving feedback, please consider the following two points: 1. Please mention in your positive comments what you thought was done well, and mention in your negative comments how the article can be altered to better suit your needs/expectations; 2. If you intend on criticizing "missing" information that you feel would be relevant to this hub, please be sure you read through all of the other hubs in this Snake Venom series first in order to see if your concerns are addressed elsewhere.

If you enjoyed this article and would like to find out how you can help support snake venom research examining the pharmaceutical potential of various snake venom compounds, please check out my profile. Thank you for reading!

© 2012 Christopher Rex

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