Snakes: Head Shape and Shields  

The head of a snake has many head-shields (scales) and two main head shapes.

Around its eyes, a snake has 8 shields: two pre-ocular (front-eye) shields, two post-ocular (back-eye) shields, two supra-ocular (above-eye) shields, and two sub-ocular (below-eye) shields.

Between the two supra-ocular shields, on the top of its head between its eyes, a snake has a frontal shield (usually in the shape of an hour-glass) and two pre-frontal shields.

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Near its nostril, a snake has a rostral shield, as well as several nasal shields, and two inter-nasal shields.

Between its nostril and its eye, a snake has two loreal shields.

Under its chin, a snake has an anterior (front) chin shield and a posterior (back) chin shield, as well as a mental shield, several upper labial (lip) shields, and several lower labial shields.

On the top of its head, a snake has two large parietal shields (usually in the shape of a coffin).

At the side of its eyes, towards it body, a snake has several temporal shields (first row and second row). It also has ventral (underside) shields.

The shape of a head’s snake can often tell which one might be venomous and which one might be non-venomous.

Non-venomous snakes generally have a spoon-shaped, rounded head.

Some venomous snakes have more of a triangular head. Also, some venomous snakes have a narrow head with bulges where their venom glands are located.

Snakes have a heat sensor on their head.

Some venomous snakes have a small depression (dent) between their eyes and their nostril. This is called a pit. The pit can sense the heat emanating from its prey. Coral snakes, which are venomous, do not have a pit – the coral snake is a sea snake.

 

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Snake

Ptyas Scalation from G.A. Boulenger’s Fauna of British India (1890)

 

Photographer: Martina Nicolls

Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM

 

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