How snakes sense their prey

Vision:
In general, snakes have good vision but it’s better developed in tree-living snakes than in burrowing species. Snakes do not have eyelids and their eyes are always open, even when they are sleeping. They have a thin scale covering the eye to protect it. Most snakes can see in black and white, and only some can see in colour.

Vibration:
Snakes do not have any ears, so they cannot hear any sounds. They rely on detecting vibrations transmitted from the ground to their lower jaw bones. This means that snakes can’t hear you scream but they could feel your footsteps if you walk by close to them. Snakes are very sensitive to these vibrations.

Smell:
Snakes use their tongue for smelling. The tongue can pick up molecules in the air and these are processed in the mouth by a special organ called the Jacobson’s organ, which tells the snake what it is smelling. A snake’s tongue cannot sting or hurt you in any way. Snakes can also detect smell through their nostrils.

Heat Sense:
The ability to sense infrared has evolved independently in pit vipers, boas, and pythons. In Africa, only the pythons have heat-sensing pits located just above the mouth on either side of the snout. The pits enable snakes to detect thermal radiation from their environment around them and they can form a picture from this. This ability helps the snake to detect prey, even in pitch darkness.

African Snakebite Institute