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A Wilder View: Rattlesnake warning signals

Posted at 10:39 AM, Jun 23, 2021

MISSOULA — We delve into one of nature’s most spectacular communication signals -- the rattlesnake rattle – for this edition of A Wilder View.

Rattlesnakes are the newest and most evolved snakes in the world. And for good reason -- they have a highly effective warning signal.

More than likely at some point in your life you have heard the distinctive sound of a rattlesnake's tail.

If you hear the sound while out on a local trail your first thought probably isn’t wondering how it makes that sound.

Once you’re in a safe spot you may ponder the answer.


The rattles are actually modified scales; segments of keratin, which is the same stuff that grows your hair and nails.

The segments fit loosely inside one another at the end of the snake’s tail.

Each time they shed their skin a new modified scale is left behind which adds another segment to the rattle.

This means you can’t tell the age of a rattlesnake from each rattle segment but rather how many times it has shed its skin.

Rattlesnakes also hiss a warning signal that is often overlooked.


The hissing occurs when a snake pushes out air from a small opening just behind the tongue called the glottis.

This causes structures within the glottis to rattle, creating the hissing sound

The snake's one functional lung has a large capacity, and as the snake hisses, its body may swell up or deflate.

Snakes are actually deaf to airborne sounds, so the hiss is only a warning for animals that can hear and not a means of communication with other snakes.

The actual behavior of vibrating their tail was used by a rattlesnake’s ancestor long before they even had their rattles.


This was used to tell predators that a bite is imminent.

You can actually see non-rattlesnakes do this vibrating of the tail today seen often in bull snakes.

Biologists suggest that the rattlesnake’s ancestors that were vibrating their tail may have aided the evolution into the novelty that is the rattle.