Despite their poor eyesight and limited hearing ability snakes have an excellent sense of smell. Yes, Snakes can sniff but not with their nose. They smell through their forked tongues which take the help of Jacobson’s or vomeronasal organ located inside the mouth. As we know snakes have no external ears and eardrums, they do not hear sounds. But these forked tongues help to sense the vibrations on the ground besides helping them to smell. By watching a snake carefully you can understand that it starts flicking its tongue while it is trying to sense the smell or sense the sound vibrations.
A groove in the top lip of the snakes helps to flick its tongue in and out without opening its mouth. So when it constantly flicks its tongue with this groove called as rostral groove it can sense the smell. Rostral groove in the upper lip is just between the two nostrils.
Well, a professor of ecology and evolutionary biology at the University of Connecticut said that, “Snakes do have a regular nose.” “The idea is that they smell something with their nose and if it’s something interesting to them that will trigger tongue-flicking behavior,” he added.
Snake flicks its forked tongue into the air which allows it to sense smell from all different directions. After taking the smell chemicals from the air, those chemicals are mixed with the fluids in the mouth and then the tongue is placed into a smell/tasting organ called vomeronasal organ (VNO). This organ inside the mouth on the upper palate works by sensing the chemicals that a snake collects from the air.
The forked tongue with the smell chemicals mixed with the fluid in the mouth sticks the two forks into two tubes of the organ. And if the two tips usually called as tines do not get stick to the separate holes of the vomeronasal organ, the snake do not get the directions of the chemical traces of its surroundings.
Once the organ stimulates the information or signals are sent into the olfactory bulb in the brain through nerves. It is only when the two tines are delivered exactly to the separate holes the snake can identify the stereo smell which helps it know the direction of its prey whether it is on its right of left. The brain of the snake probably have fraction of seconds to interpret or process the information sent.