As part of Fortnightly topic challenge #3: Creature Design

I am looking for a realistic way to create a particularly nasty creature.

What I would like:

  • A creature that is capable of emitting a sonic 'noise'...maybe wave is a better term
  • This ability should allow the creature to render higher order creatures stunned or unconscious for 30+ seconds, I would prefer the effect NOT be permanent.
  • By higher order I mean vertebrates essentially, if all vertebrates creates a problem specifically it should work on humans
  • Is a predator of the creatures it stuns


  • Can this be accomplished biologically?
  • What would the mechanism for such a skill be (both the process and the biological i.e. physical mechanism be...an extra organ maybe?)
  • How would this animal protect itself from its own abilities?
  • Are there any physical limitations having this power would necessitate, for example if there is a mechanism for this could it be slotted into a bear, a monitor lizard, maybe a kangaroo?
  • $\begingroup$ Porpoises can already do this to smaller sea creature. $\endgroup$ Commented Mar 10, 2015 at 4:04
  • $\begingroup$ Do you mean something like Banshee (en.wikipedia.org/wiki/Banshee_%28comics%29)? $\endgroup$
    – jnovacho
    Commented Mar 10, 2015 at 12:34
  • $\begingroup$ @jnovacho something like that yes. $\endgroup$
    – James
    Commented Mar 10, 2015 at 13:19
  • 6
    $\begingroup$ So, "screeching human toddler" isn't a viable answer, then...? $\endgroup$
    – J.D. Ray
    Commented Jun 8, 2016 at 20:32
  • 2
    $\begingroup$ @J.D.Ray Considering I have one of those I feel like that could count lol. I have been "stunned" or at least disoriented by long duration child screaming. $\endgroup$
    – James
    Commented Jun 8, 2016 at 20:33

10 Answers 10


So, you want to build a banshee.


The pistol shrimp is an interesting example, but ultimately won't work. It snaps open its claw so quickly that a cavitation bubble is created. This creates an acoustic wave of 80kPa (218 dB) at a distance of 4 cm from the claw. It's enough to kill small fish.

However, underwater acoustics are less impressive in air, so this won't directly translate.

In the air, against higher-order vertebrates, there are only artificial sonic weapons. The best examples have been used for deterring pirates and dispersing crowds, they are called long range acoustic devices.

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To make this most effective for an animal, it would be best to use ultrasound frequencies.

Studies have found that exposure to high intensity ultrasound at frequencies from 700 kHz to 3.6 MHz can cause lung and intestinal damage in mice. Heart rate patterns following vibroacoustic stimulation has resulted in serious negative consequences such as atrial flutter and bradycardia.


That's frequency, the other component would be the sound pressure.

Tests performed on mice show the threshold for both lung and liver damage occurs at about 184 dB. Damage increases rapidly as intensity is increased.

Now, dB is not a unit of pressure, it's a ratio of pressure, and thus unitless. But we can convert it to pressure easily. Additionally, saying 184 dB doesn't mean a lot without an associated distance, but we're stuck without that information. All we can calculate is that about 31.6kPa is being exerted somewhere along the travel from the transmitter to the receiving animal (most likely, though, it's at the surface of the animal).

From this we can assume your creature will need to generate less than 184 dB acoustic waves in the ultrasonic range and be close range to the target for an attack.

Note about volume

It's important to point out that 184 dB is really loud. The loudest non-bass acoustic instrument appears to be the trombone, peaking around 114 dB. Many times quieter than required. Some bats have been recorded at 135 dB. The loudest land animal is possibly the howler monkey, topping out around 140 dB. I know it seems like 140 dB is pretty close to 184 dB. It's not. Decibels are a logarithmic scale. Every 3dB increase is a doubling in power. In air, 140 dB is only about 200 pascals (rms) while 184 dB in air is 31,698 pascals (rms). A 140 dB sound is like a jet engine 100 feet away, 185 dB kills hearing tissue, and 194 dB is the loudest sound possible in our atmosphere.


It might not be impossible that a creature could produce such a sound. But it's highly unlikely. It's orders of magnitudes higher than any existing biological sound. However, that is the maximum before permanent damage occurs. For your creature, it needs significantly less than that for stunning alone.

So, such a creature is entirely in the realm of possibility. Even a howler monkey could disorient you with a scream if it had a mind to.

With that background, on to your questions.

Can this be accomplished biologically?

Yes, a set of lungs and an enlarged hyoid bone will do the trick.

What would the mechanism for such a skill be?

It would likely be vocalization. Though other possibilities exist, stridulation comes to mind, and that would certainly look menacing.

How would this animal protect itself from its own abilities?

It's a good bet that the creature itself is deaf or in the process of making the sound, temporarily deafens itself. Bats do this. When bats call for echolocation, a tiny muscle holds their bones of hearing in place while they echolocate so they don't deafen themselves.

Are there any physical limitations having this power would necessitate?

This depends on the method used to create the sound. The most effective would be an array of sources, either vocal or stridulatory organs. This would allow for more directionality and focus. This would make the attack more effective over a longer distance and use less energy to generate.

The problem

It's really easy to avoid this attack. Simply wear ear plugs. Better yet, use active ear plugs, they simply don't transmit any sounds above a certain decibel level. Deaf people are inherently immune.

  • 1
    $\begingroup$ I don't think that you can protect your lung or liver tissue by putting fingers (or anything else) in your ears. After all, the damage comes from the sound wave physically hitting the tissue, not from you hearing it. $\endgroup$
    – celtschk
    Commented Mar 9, 2015 at 19:37
  • $\begingroup$ @celtschk That's at the maximum, we're specifically targeting volumes below that maximum. For disorientation caused by the sound itself, that is primarily through hearing. $\endgroup$
    – Samuel
    Commented Mar 9, 2015 at 19:39
  • 3
    $\begingroup$ I would give this a second upvote for suggesting stridulation if I could. $\endgroup$
    – James
    Commented Mar 10, 2015 at 15:23
  • $\begingroup$ Would ear-plugs really work against the Long-Range-Acoustic-Device? Seems like a very cheap way to overcome the cost of such a device. (though, not many people carry ear-plugs on them) Is it the (ratio of) pressure or the sound which causes pain? $\endgroup$ Commented Oct 23, 2015 at 15:48

It's already been done.

Two species of moth, the hawkmoth and the tiger moth, use not just sonic but ultrasonic signals to defend themselves from bat attacks. The hawkmoth has only recently been discovered to do this.

How? They use their genitals. No, I'm not joking. Have a look at this video (from Scientific American) showing the effect in action - the sound isn't that clear as our hearing range only goes up to ~21kHz and ultrasonic is above that, but the middle part of the video shows the process very clearly. (Perfectly SFW but your boss might throw you some strange looks...)

There are several different papers on the subject of natural sonic defense, though they are a bit long.

The best way to defend yourself against your own weapon is to make sure it's outside of your hearing range. This is something that would very likely be evolved while the defence trait itself evolves: those who can hear it will also be stunned and then eaten when the predator comes to. Essentially, your hearing range just needs to be lower than that of your predator.

Although the moth sound doesn't work on humans, it wouldn't take much to bring its frequency down to our hearing range, where it would in fact be incredibly loud - it's loud in enough in the ultrasonic range to jam bats' echolocation radar. Once this is done it would likely work on most higher-order vertebrates: humans have some of the worst hearing ranges in the natural world.


With the others, dolphins will stun prey as well with sound too.

the biggest thing of course would be the generating the shock wave, sound travels better in water, it dissipates slower and can do a better job giving a punch.

So the assumption is, land based animal that can generate a stunning blow with sonics. Since we have developed sonic weapons it is feasible to believe an animal could do so too. The loudest animal on earth is the Blue Whale between 155 and 188 decibels. A jet is about 140. #2 on the list is the Howler Monkey, which can call up to 120 decibels.

Now, for many species, you don't necessarily need just loud, but certain pitches can be very effective. High pitched sounds can be very disorienting for mammals, walking by the town siren when it goes off the first Wednesday of the month will make it hard for me to walk in a straight line. You also have large displacements of air. Flash bangs are just a loud boom that displaces enough air to mess with an inner ear. Having a croak like a frog on a large beast with directional capabilities could be a stunning blow, but those would have to be a little closer, high pitched sounds would have a larger distance but could also be directional, increasing it's effectiveness.

  • 3
    $\begingroup$ It's important to note the 188 decibels in water and 140 decibels in air are very different things. Your source doesn't seem to recognize that a decibel is the log of a ratio and can't be compared directly unless they used the same reference, which water and air do not. $\endgroup$
    – Samuel
    Commented Mar 9, 2015 at 19:46
  • $\begingroup$ @Samuel very good points. $\endgroup$
    – bowlturner
    Commented Mar 9, 2015 at 19:48

It's quite possible...and not simply through hearing. Sadly, humans over the age of 20 have experienced enough hearing degradation that it's difficult to disable them through sound without some more permanent effects such as breaking the ear drum itself.

That said...Infrasound is likely what you want to go with here. Our ears are actually capable of picking it up, but it's never actually transmitted through to the brain. But more distrubingly, these infrasounds can cause our eyeballs to vibrate, which causes 'visions', mass discomfort, and a bunch of confusion.

Vic Tandy (http://en.wikipedia.org/wiki/Vic_Tandy) :

Tandy went on to recreate his experience, and with the assistance of Dr. Tony Lawrence, he was able to publish his findings in the Journal of the Society for Psychical Research.[12] Their research led them to conclude that infrasound at or around a frequency of 19 Hz,[2][10][13] has a range of physiological effects, including feelings of fear and shivering.[7][14] Though this had been known for many years, Tandy and Lawrence were the first people to link it to ghostly sightings.[8][14]

19 hertz is a very low frequency...elephants and hippo's can actually generate these sounds, but it's generally relegated to large creatures. Some whales as well.


Just random thoughts:

You don't have to focus on the intensity/volume of sound to achieve these effects. Pitch and modulation can have dramatic effects on all manner of things, ultra-low frequencies can stop your heart (urban legend, but not outside of the realm of possibility if framed correctly), high frequencies can disrupt your balance, soundlessness can drive you insane, irritating sounds can do that as well: It is easily imagined that the right combination can do any number of delightfully nasty things.

High intensity sound is fairly easy to detect and block, and it is self limiting: If you do it too often to break your prey's ability to hear. Once you've deafened the nearby prey, they can fight back effectively.

Also... frequency specific attacks would logically evolve with an immunity to them, though volume based attacks COULD do the same, the intense physical resistance a creature would need to use them (at human scale, I'm thinking about not just somehow protecting the hearing, but the bone and organs from presumably very intense bursts of vibration).


The Pistol Shrimp uses an oversized and specialized claw to create a sonic blast which can stun or kill its prey, and I believe I read dolphins or porpoises using sonics to stun fish as well. Underwater may not be your goal, but sonics do get used by exixsting lifeforms so now its just research and adaptaion to fit your requirements.


Sperm whales hunt giant squid; How the whales manage to subdue such able prey has been a mystery. One hypothesis, proposed more than 20 years ago, speculated the whales used powerful ultrasound shrieks to knock their squid prey senseless before scooping them up. Like bats and dolphins, some whales use ultrasonic clicks to find prey and navigate. The basic premise is that that, since sound travels faster underwater, that a beam of sound(echolocation) that is narrow enough could kill in the same way shockwaves do; by rupturing the organs of the animal.

A few helpful links of weaponized echolocation;

  1. http://www.livescience.com/7297-whales-attack-squid-mystery-deepens.html
  2. http://www.science20.com/squid_day/do_sperm_whales_use_sonar_stun_giant_squid

So this is way out there, and the chance of such creatures existing is so unlikely I don't even want someone else doing the math, let alone having to do the math myself. Let's say this is just a “LITTLE” bit contrived. I can imagine two ways for this to work, that don't rely on concussive force or infrasonic something. One method absurd and one plain crazy. I let you decide which is which.

  1. Sensory overload occurs when the conscious mind is overwhelmed by stimuli. One way to do this is sound. But seeing as sight trumps all other senses in perception. It would need to be an animal or animals that lives and hunts in the dark. To overwhelm the brain you need the veritable big brother plus the grandfather of cacophonies of different and disharmonious sounds. So I'd say a cave dwelling, carnivorous swarm of beetles. They'd need to be able to produce malleable sounds like crickets maybe plus in a cave you get the echo to multiply the sounds. I know that a swarm would just rush you and eat you, but that wasn't the question. Just for reference sensory overload can lead to a wide variety of effects from mild irritation to fainting. Seriously its beetles now idea if that would work on a beatle, how much memory do they have to be overloaded.
  2. It is neither a quick, nor easy method saying nothing about the likelihood nor feasibility. Hypnotherapists say that around 25-30% percent of humans can't be hypnotized. The remaining humans range from easy to I'd rather climb the Everest. Sound alone can induce trance states in two ways I know of: By recurring monotonous sound like waves, white noise or red noise and lowering the heart rate awareness etc. this way until you got one hypnotized dinner. Or by two different frequencies of tone that don't disparage too much. For example hit the right ear with 500 hertz and the left with 510 and the brainwaves of the listener will mimic that 10 hertz difference sink the guy into trance. Bon appetit. No idea how either of those to work as part of animal, but I couldn't come up with another method to incapacitate someone with sound alone. Unless you find an animal that can play music then if got a third crazy way to do this. Can't hypnotize anything without subconsciousness, so much for self-defense.
  3. Music can influence the heartbeat, which can lead to low blood pressure, which causes the brain to be underfed with O2, which in turn lets you faint. Made something else but music would do the trick here. I couldn't find anything where it did though. Don't know maybe they can plug their ears somehow if animals are even effected by this.

Killer whales use resonance to upset herring, and then a tail slap to stun them in this BBC wildlife show (Oceans). My physics isn't good enough to say if what the whales are up to can be done in air.

Alternatively, could your sonic attack be the biological equivalent of a flashbang grenade? A bombardier beetle chemical attack. Spit or throw something at a target.


I would suggest one of two variations,

  1. Similar to a frog's air pouch, it could produce a large amount of air and force it through an opening, similar to a human throat.

It can control the throat muscles, reducing or increasing the air flow to manipulate the pitch and volume of the sound, thus creating a 'screech' or 'him.' This can cause a variable effect on the target by using ultrasonic or infrasonic effects. The 'screech' could liquefy the internal organs of vertebrae, whereas the 'him' of infrasonic would disturb the liquid in a body causing the effects of nausea and a variety of effects on a being;

  1. Alternatively, it can be a crustacean where again it utilizes an air pouch but has holes in certain places of its' shell to which it can manipulate a 'whistle' at certain pitches to disorient its' target.

I have no degree and barely understand the science behind sound manipulation, but I'm fairly intellectual and have thought about similar situations myself, thus the answers I've given. Please forgive me if I've overlooked something.

  • $\begingroup$ You seem to have stopped in the middle of writing this. $\endgroup$
    – JDługosz
    Commented Jun 9, 2016 at 16:52
  • $\begingroup$ (And "its" is the pronoun. There is no trailing apostrophe. ) $\endgroup$
    – JDługosz
    Commented Jun 9, 2016 at 16:53
  • $\begingroup$ I believe this is the full answer, but the formatting for suggestions 1 and 2 are different. I submitted an edit request to try and clear it up in case they do not return soon. I hope it retains the original message, as I did make a few grammatical changes in areas that confused me. $\endgroup$ Commented Jun 9, 2016 at 17:35

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