Anyone lucky enough to observe a snake will likely notice that the animal constantly flicks its tongue as it negotiates its environment. The reason for this is that snakes have something called the Jacobson’s organ that provides a particularly interesting sense – chemoreception. This organ is part of the olfactory system and is comprised of a patch of sensory cells that can detect chemical particles transporting the information to the brain for processing.
The Jacobson’s organ is not restricted to snakes and lizards but very common amongst many different higher animal types – from elephants to monkeys, turtles to cats, dogs to salamanders and many critters in between! Even humans have a vestigial Jacobson’s organ that some researches believe may become activated in pregnant women, accounting for the improved sense of smell often reported and could perhaps be involved in morning sickness.
In snakes the crescent shaped Jacobson’s organ is located on the roof of the mouth and contains a sensory pit on each end. When the snake flicks its forked tongue it is ‘tasting’ the air, each fork pics up chemical cues which are then transported to the two pits of the Jacobson’s organ – the right fork to the right pit and the left fork to the left pit. This separation allows snake to distinguish between the two sides of the fork and tell from which direction a particular scent is coming. This is vitally important as it allows the snake to track prey, detect predators and find mates.