Snake Dentition

Snake dentition is a complex subject and helps scientists to distinguish very different categories of snake.

The first important distinction to be made is between snake teeth and snake fangs. All snakes have teeth but they are not used for chewing food as mammal teeth are – snakes swallow their food whole. Snake teeth are solid and not designed to deliver venom. They are angled backwards to hook the snake’s live prey and prevent it from sliding out of the mouth and escaping.

Some snakes, like pythons, only have fixed, solid teeth and deal with their prey by constriction, not by the injection of venom. Other snake species, however, have fangs as well as teeth. Snake fangs are hollow or grooved and are attached to venom sacks and are used for injecting venom into prey.

In this article we will tackle the subject of snake dentition by looking at the placement of fangs in the snake’s mouth, e.g. front fanged or back fanged as well as the structure of the different types of fang e.g. hollow, front grooved.

Snake teeth can be categorized into four different groups, summarized in the chart below and then explained in greater detail

Notes

1. All these names include the Greek word “glyph” which means “groove”
2. Fang type determines efficiency of venom delivery. A hollow fang delivers venom directly into prey without waste. Venom will mostly flow through a grooved fang but some be wasted on contact with prey skin.

Aglyphous

• Means “lacking in grooves”
• All teeth are solid, without grooves or specialized venom-injecting fangs
• All teeth are similar in shape and size
• These teeth are for gripping prey during swallowing
• Most snakes with only these teeth are non-venomous and are harmless to humans.
• Includes snakes such as the python (which constricts its prey rather than bites it) and primitive blind snakes. 

Solenglyphouse

• Means “Pipe Grooved”
• The fangs are hollow or tubular and very sharp, like a hypodermic needle
• The hollow core leads venom from the venom gland at the entrance orifice near the base and injects it from a slit-like exit orifice on the front of the fang near the tip

• The fangs are long (much longer than other types of fang) and can make up to half the skull’s length.
• These fangs are attached to the jaw by hinges and fold up against the roof of the mouth when the mouth is closed. They swing forward when the mouth is opened to bite, up to 180 degrees.

• The fangs penetrate deep into their prey and inject large quantities of venom
• When the snake strikes and closes its jaws, compressor muscles deliver venom at high pressure. (Their venom is usually less powerful than some other snakes but in large quantities can be lethal).
• These snakes strike their prey and release – then hunt down the prey as the venom takes effect
• These fangs are unique to vipers
• Includes snakes such as the Gaboon viper and puffadder

Proteroglyphous

• Means “Forward Grooved”
• These snakes have very few teeth except for their enlarged fangs
• The fangs are located at the front of the mouth
• Fangs point downwards, are short and hollow. They are not hinged and fit into the mouth.

• Snake must strike and then hang onto its prey in order to inject venom. Some species will even envenomate (inject venom) AND constrict, which subdues and kills their prey more efficiently
• Some proteroglyphs have partially movable fangs, including the most dangerous species such as mambas, taipans, and death adders
• IThis category includes snakes such as the cobras, mambas, coral snakes, sea snakes, and more.
• A few, such as spitting cobras, have modified front-facing exit holes and special muscles to increase the velocity with which venom is ejected or “spat”(for at least 2 meters).

Opsthoglyphous

• Means “rear grooved”
• Have enlarged teeth in the back of their jaw, behind the normal teeth

• These enlarged teeth are grooved to channel venom
• These snakes have an under-developed venom delivery system (called a Duvernoy’s gland) that cannot store venom or inject venom forcefully. Venom is released by “chewing,” – the more they chew, the more venom is delivered to their prey. This venom plays a bigger role in digestion than other species with different dentition. 
• There are exceptions such as the African Boomslang (Dispholidus typus) whose Duvernoy’s glands produce potent venom and are partially muscled which makes the boomslang potentially dangerous. Bites from other rear-fanged snakes are known to cause relatively mild, transient, and local symptoms
• The snake must quickly move prey to the back of its mouth to inject the venom
• Includes snakes such as the Boomslang, Dispholidus typus and the Bird snakes, Thelatornis spp.

Venom harvesting and History of Fang development – see video below