Why Do Snakes Have Forked Tongues?

It’s the most infamous tongue in the world.

To us, the snake's forked  tongue means danger and deceit.

But to a snake, all that flicking lets it  paint a picture of the world around it.

We mostly rely on sight and sound,  but snakes live in a world of smell.

Like us, they use their nose  for some basic sniffing.

See its nostrils there?

But it’s their tongue that takes their senses to the next level -- helping them skirt  danger, find a mate and hunt for prey.

This mouse might be quick and quiet,   but it can’t help leaving a trail of clues  behind ... perfect for a hungry snake to follow.

The snake flicks its tongue in a blur of up and down  motion, collecting scents from the air and ground.

You might’ve heard that snakes taste the air  with their tongue, but that's not quite right.

Snakes don’t actually have taste  buds on their tongues at all The tongue’s whole job is to collect samples   in the saliva and bring them  back into the snake’s mouth.

Its forked tongue ends in two  delicate tips called tines.

They allow the snake to sweep a wider area and   pick up odor molecules from two  different spots at the same time.

When it retracts, the forked tongue fits   perfectly into this tongue-shaped  groove in the roof of the mouth.

Saliva from the tines flows  through these two tiny holes,   one on each side -- up into  the vomeronasal organs.

They’re full of sensory cells, ready to pick  up the tiniest trace of that appetizing mouse.

The snake’s brain compares cues from the left and   right to instantly figure  out which side is stronger.

Yup, snakes smell in stereo.

And that’s bad news for the mouse.

Researchers at the University of Connecticut   set up high-speed cameras to take a  closer look at that forked tongue.

In a single, one-second flick,   they captured how a snake waves its  tongue up and down, up to 15 times.

Compare that to their lizard cousins that usually  just pop their tongues out and down to the ground.

That means the lizards are mostly  picking up odors from surfaces.

The researchers set up lasers and found that   the snake's lightning-fast tongue rips  through the air, creating vortexes ... … which suck in air and concentrate  odor molecules in the saliva.

When a mammal tries to find the source of a  scent, it points its nose in the air and sniffs.

That also works to concentrate scents, but the  snake can still smell circles around the mouse.

With such a finely tuned sensory system,   it isn’t long before that tongue  leads the snake right to its prey.

A tongue that tastes dinner is good, but a  tongue that finds it for you is even better.