6 ms·

Tiger moth jams bat sonar (2009)

44 points by FergusArgyll 3y ago

FirmwareBurner 3y ago
Waiting for bats to develop laser range finding capabilities.
jimnotgym 3y ago
Ok it jams sonar, but you don't need sonar if the target is making a noise, you just listen, don't you? I couldn't read the full paper but the abstract didn't mention that they were going to discuss how the jamming worked
- geomark 3y ago
  I think the bats do need sonar because they use it for echo ranging. You need an echo to determine range.
- icebreaking 3y ago
  I could read the full paper and man they definitely talked about a few different noises the moths make and how effective each one is at deterring preying bats.
- adrian_b 3y ago
  Free full paper: https://www.researchgate.net/publication/26676734_Tiger_Moth_Jams_Bat_Sonar https://www.researchgate.net/publication/26676734_Tiger_Moth... Besides the fact that the sonar is needed for accurate ranging, as mentioned by another poster, these moths produce their sounds in response to the bat sonar, so their sounds would not be useful to find them without sonar. As mentioned in the paper, there are also other kinds of moths which are poisonous and which do not jam the sonar, but which emit warning sounds that the bats learn to avoid. Other moths also emit sounds, but those sounds do not prevent bats from hunting them, except perhaps for the first few times until a bat learns that those moths emitting sounds are good to eat, so their sounds do not have a jamming effect.
- exDM69 3y ago
  Bat (and human) echolocation is not based on distinguishing sonar pings in time domain, but rather listening to the frequency spectrum of the reverberating sound, ie. "measuring" the impulse response of the surroundings. Sending a signal that resembles the echo pulses will skew the spectrum and confuse the listener. In theory that information can be used to triangulate the "jammer" if you could measure the small difference in time from receiving in left vs. right ear but that's not how mammal brains process auditory signals. So it's not like sonar in submarine warfare with hydrophone arrays and digital signal processing.
  - thomastjeffery 3y ago
    I don't know about bats, but humans most certainly do both.
    - exDM69 3y ago
      Yes, but not at a resolution that would be useful for echolocation. Humans can't distinguish individual echo pulses with millisecond granularity needed for meter-scale accuracy, yet humans can learn bat-like echolocation skills.
      - thomastjeffery 3y ago
        I think the distinguishing factor is distance vs. direction. We can very accurately measure direction by hearing the difference of time between ears, but that alone doesn't measure distance.
        exDM69 3y ago
        The ability to distinguish direction from a sound is based on the human ear frequency response being very directional. Your left ear will hear a sound coming from the right very differently than from the left. This is predominantly because of the shape of your ear and your head being in the way. There's no way humans can tell the time difference of about 50 microseconds between hearing with your left and right ears. If you have research to prove otherwise, I'm all ears (pun intended). You can also easily tell the difference of sound coming from directly ahead vs behind despite the ears hearing the sound simultaneously. There is a lot of research into psychoacoustics in the past few decades. And pretty cool demos where directional audio is generated on headphones by altering the frequency spectrum between left and right ears.
resolutebat 3y ago
Nice garden path sentence title there: both "jams" and "bat" have several completely different meanings and it took a while until my brain permutated the right ones. (Tiger moth) jams (bat sonar).
- shard 3y ago
  At first read I thought the title was a secure password example along the lines of "correct horse battery staple": https://xkcd.com/936/ https://xkcd.com/936/
- magnusmundus 3y ago
  I also had some fun thinking on a tiger moth jam, and how that may have batted a sonar.
- d1sxeyes 3y ago
  Tiger also has its own meaning, which makes the parsing even harder. Both 'tiger moth' and 'bat sonar' are noun phrases in which the first word is not the actual meaning of the phrase. So you have two of these weird noun phrases, topped off by ambiguity about the verb ('jam' vs 'bat'). Very tricky sentence to wrap your head around!
  - thaumasiotes 3y ago
    > Both 'tiger moth' and 'bat sonar' are noun phrases in which the first word is not the actual meaning of the phrase. So you have two of these weird noun phrases That's not weird; it is the norm for English by a ridiculous margin. We do have some left-headed compounds ("pickpocket"), but they are very noticeable exceptions to an extremely strong rule.
    - OJFord 3y ago
      Surely 'pickpocket' is that way because (there) 'pick' is a verb, not a noun? Like.. 'roast potato' or 'tryhard'. (To deviate way off course, isn't it also odd we don't say 'roasted potato', or 'roasted chicken', etc.? Or not in that context anyway, only if it was something like 'mashed or roasted?')
FrustratedMonky 3y ago
I wonder if moths being 'soft' is also an adaptation. Is there any study that moth 'soft' covering is also a sound absorber, to allude bats. I didn't see it mentioned here.
- zimpenfish 3y ago
  zefrank mentioned this briefly in his latest video[0] showing a paper titled "Thoracic scales of moths as a stealth coating against bat biosonar"[1] [0] https://www.youtube.com/watch?v=v-s714RNXHY https://www.youtube.com/watch?v=v-s714RNXHY [1] https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0692 https://royalsocietypublishing.org/doi/10.1098/rsif.2019.069...
  - pama 3y ago
    That also makes a nice garden path passphrase: soft tiger moth scales evade bat sonar.
FergusArgyll 3y ago
Here's the relevant wiki page for reference. https://en.wikipedia.org/wiki/Echolocation_jamming https://en.wikipedia.org/wiki/Echolocation_jamming
gregfjohnson 3y ago
There’s a fantastic book called “An Immense World” by Ed Yong that covers the incredible range of sensory modalities found in nature. One of the chapters goes into depth on bats and sonar.
pseudolus 3y ago
There have been a number of articles that have highlighted the ongoing evolutionary development of measures and countermeasures with respect to bats and insects over the last 60+ million years.[0] Sort of a natural landscape that mirrors the ongoing battle in military developments (radar, stealth, etc). [0] "Sound strategies: the 65-million-year-old battle between bats and insects" https://pubmed.ncbi.nlm.nih.gov/21888517/ https://pubmed.ncbi.nlm.nih.gov/21888517/ "Moths and bats: An evolutionary war" https://www.nhm.ac.uk/discover/evolutionary-war-between-moths-bats.html https://www.nhm.ac.uk/discover/evolutionary-war-between-moth...
- andsoitis 3y ago
  it's all an arms race for increased chances to produce offspring.

44 points by FergusArgyll 3y ago

Waiting for bats to develop laser range finding capabilities.

Ok it jams sonar, but you don't need sonar if the target is making a noise, you just listen, don't you? I couldn't read the full paper but the abstract didn't mention that they were going to discuss how the jamming worked

geomark 3y ago
I think the bats do need sonar because they use it for echo ranging. You need an echo to determine range.
icebreaking 3y ago
I could read the full paper and man they definitely talked about a few different noises the moths make and how effective each one is at deterring preying bats.
adrian_b 3y ago
Free full paper: https://www.researchgate.net/publication/26676734_Tiger_Moth_Jams_Bat_Sonar https://www.researchgate.net/publication/26676734_Tiger_Moth... Besides the fact that the sonar is needed for accurate ranging, as mentioned by another poster, these moths produce their sounds in response to the bat sonar, so their sounds would not be useful to find them without sonar. As mentioned in the paper, there are also other kinds of moths which are poisonous and which do not jam the sonar, but which emit warning sounds that the bats learn to avoid. Other moths also emit sounds, but those sounds do not prevent bats from hunting them, except perhaps for the first few times until a bat learns that those moths emitting sounds are good to eat, so their sounds do not have a jamming effect.
exDM69 3y ago
Bat (and human) echolocation is not based on distinguishing sonar pings in time domain, but rather listening to the frequency spectrum of the reverberating sound, ie. "measuring" the impulse response of the surroundings. Sending a signal that resembles the echo pulses will skew the spectrum and confuse the listener. In theory that information can be used to triangulate the "jammer" if you could measure the small difference in time from receiving in left vs. right ear but that's not how mammal brains process auditory signals. So it's not like sonar in submarine warfare with hydrophone arrays and digital signal processing.
- thomastjeffery 3y ago
  I don't know about bats, but humans most certainly do both.
  - exDM69 3y ago
    Yes, but not at a resolution that would be useful for echolocation. Humans can't distinguish individual echo pulses with millisecond granularity needed for meter-scale accuracy, yet humans can learn bat-like echolocation skills.
    - thomastjeffery 3y ago
      I think the distinguishing factor is distance vs. direction. We can very accurately measure direction by hearing the difference of time between ears, but that alone doesn't measure distance.
      - exDM69 3y ago
        The ability to distinguish direction from a sound is based on the human ear frequency response being very directional. Your left ear will hear a sound coming from the right very differently than from the left. This is predominantly because of the shape of your ear and your head being in the way. There's no way humans can tell the time difference of about 50 microseconds between hearing with your left and right ears. If you have research to prove otherwise, I'm all ears (pun intended). You can also easily tell the difference of sound coming from directly ahead vs behind despite the ears hearing the sound simultaneously. There is a lot of research into psychoacoustics in the past few decades. And pretty cool demos where directional audio is generated on headphones by altering the frequency spectrum between left and right ears.

resolutebat 3y ago

Nice garden path sentence title there: both "jams" and "bat" have several completely different meanings and it took a while until my brain permutated the right ones. (Tiger moth) jams (bat sonar).

shard 3y ago
At first read I thought the title was a secure password example along the lines of "correct horse battery staple": https://xkcd.com/936/ https://xkcd.com/936/
magnusmundus 3y ago
I also had some fun thinking on a tiger moth jam, and how that may have batted a sonar.
d1sxeyes 3y ago
Tiger also has its own meaning, which makes the parsing even harder. Both 'tiger moth' and 'bat sonar' are noun phrases in which the first word is not the actual meaning of the phrase. So you have two of these weird noun phrases, topped off by ambiguity about the verb ('jam' vs 'bat'). Very tricky sentence to wrap your head around!
- thaumasiotes 3y ago
  > Both 'tiger moth' and 'bat sonar' are noun phrases in which the first word is not the actual meaning of the phrase. So you have two of these weird noun phrases That's not weird; it is the norm for English by a ridiculous margin. We do have some left-headed compounds ("pickpocket"), but they are very noticeable exceptions to an extremely strong rule.
  - OJFord 3y ago
    Surely 'pickpocket' is that way because (there) 'pick' is a verb, not a noun? Like.. 'roast potato' or 'tryhard'. (To deviate way off course, isn't it also odd we don't say 'roasted potato', or 'roasted chicken', etc.? Or not in that context anyway, only if it was something like 'mashed or roasted?')

FrustratedMonky 3y ago

I wonder if moths being 'soft' is also an adaptation. Is there any study that moth 'soft' covering is also a sound absorber, to allude bats. I didn't see it mentioned here.

zimpenfish 3y ago
zefrank mentioned this briefly in his latest video[0] showing a paper titled "Thoracic scales of moths as a stealth coating against bat biosonar"[1] [0] https://www.youtube.com/watch?v=v-s714RNXHY https://www.youtube.com/watch?v=v-s714RNXHY [1] https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0692 https://royalsocietypublishing.org/doi/10.1098/rsif.2019.069...
- pama 3y ago
  That also makes a nice garden path passphrase: soft tiger moth scales evade bat sonar.

FergusArgyll 3y ago

Here's the relevant wiki page for reference. https://en.wikipedia.org/wiki/Echolocation_jamming https://en.wikipedia.org/wiki/Echolocation_jamming

gregfjohnson 3y ago

There’s a fantastic book called “An Immense World” by Ed Yong that covers the incredible range of sensory modalities found in nature. One of the chapters goes into depth on bats and sonar.

pseudolus 3y ago

There have been a number of articles that have highlighted the ongoing evolutionary development of measures and countermeasures with respect to bats and insects over the last 60+ million years.[0] Sort of a natural landscape that mirrors the ongoing battle in military developments (radar, stealth, etc). [0] "Sound strategies: the 65-million-year-old battle between bats and insects" https://pubmed.ncbi.nlm.nih.gov/21888517/ https://pubmed.ncbi.nlm.nih.gov/21888517/ "Moths and bats: An evolutionary war" https://www.nhm.ac.uk/discover/evolutionary-war-between-moths-bats.html https://www.nhm.ac.uk/discover/evolutionary-war-between-moth...

andsoitis 3y ago
it's all an arms race for increased chances to produce offspring.