11 ms·

Tardigrades walk like insects 500k times their size

160 points by _Microft 5y ago

topherhunt87 5y ago
Help me out here: > the size of tardigrades (which are only about 0.02 inches long) > the creature's movement resembles that of insects 500,000 times their size 0.02 inches x 500,000 = 10,000 inches or 833 feet. Where does one find insects 800+ feet long? Or rather, how does one stay the heck away from them?
- shard 5y ago
  Length is one measure of size, but it may be volume that the title is referring to. So assuming a .02" sphere, 500k times would be about a 1.6" sphere, if my math is correct.
- Out_of_Characte 5y ago
  They define size as volume or weight rather than length, which makes sense, im 180cm long, an elephant is ~4 meters, making it twice as tall. but its weight can be 6000kg which is a factor of 100 larger than my measely 60kg. Volume grows at ^3 with increase in cubic length.
twirlock 5y ago
dang 5y ago
Recent and related: Tardigrades Walk - https://news.ycombinator.com/item?id=28380188 https://news.ycombinator.com/item?id=28380188 - Sept 2021 (29 comments) Entanglement between superconducting qubits and a tardigrade - https://news.ycombinator.com/item?id=29580686 https://news.ycombinator.com/item?id=29580686 - Dec 2021 (111 comments)
- hetspookjee 5y ago
  Thank you for linking those threads as the latter one was a thrill to read: both the thread as the paper.
tiahura 5y ago
“The team was surprised to note that the water bears did not have distinct gaits for each speed, like horses as they transition from a walk to a gallop. Rather, their locomotion closely resembled that of insects and arthropods, scurrying along faster and faster with no change to the basic step pattern.” So they expected them to walk like horses and not insects? That seems odd.
- steve_adams_86 5y ago
  I don’t know if it was an expectation so much as an observation which was then put into comparison to help explain it.
- clairity 5y ago
  what's more odd is that "...locomotion closely resembled that of insects and arthropods, scurrying along faster and faster with no change to the basic step pattern" is completely wrong. many insects and arthropods change gaits/step patterns with speed. it's practically required, as you get beyond optimal energetics pretty quickly (like being stuck in the wrong gear too long on a bike). cockroaches, for instance, only use their back 4 legs when 'running', and will use only their back 2 legs when all out 'sprinting'. we humans start jogging and then running as speed increases for the same reason, it's not energetically efficient to just 'walk faster'.
- jakear 5y ago
  Probably not as easy to secure additional funding/headlines when the tagline is “tardigrades move in the simplest conceivable manner, much like other simple creatures”.
- ru552 5y ago
  I think they were just trying to express that animals generally change their gait as they increase speed. These specific animals do not, which is akin to insects.
sebow 5y ago
This has been known for a while now, but it's definitely still fascinating.Also it reminds me of another similar comparison: humans "walk" like proteins on microtubes.
1024core 5y ago
> "Other times, they’d see something they like and run towards it.” Can tardigrades really "see" in the traditional sense? Can they make out shapes, etc.? Do they have photo receptors plugged into the brain?
- jbotz 5y ago
  They can't "really see"... they have eyespots with just a handful of light-sensitive cells and no lenses, so it's just gradients of light and dark. But they have other senses and I think the word "see" was metaphorical here, meaning they sensed the presence of an attractive stimulus. In some ways the real meaning of "see" doesn't depend on optics, you see?
  - throwamon 5y ago
    According to a video from another comment, each eyespot is a single cell. https://www.youtube.com/watch?v=kux1j1ccsgg https://www.youtube.com/watch?v=kux1j1ccsgg
  - scotty79 5y ago
    I don't know. They seem to be able to squeeze out a lot of funtionality out of very limited numbers of cells. I wouldn't be surprised if at some point it was discovered that their light sensitive cells slosh around the cytoplasm inside the roughly spherical cell wall turning it into ad-hoc lenses even if for a brief moment. It still might be enough to get light intensity in a specific direction.
jcims 5y ago
With a few minutes of googling the only reference i can find says that Tardigrades have approximately 200 neurons in their brains [1] and their dry weight is on the order of one microgram [2]. They also have a lower count of synaptic connections (from the same paper): >Thus, miniaturisation of the tardigrade nervous system is achieved largely by reducing cell numbers, neuropil branches and the number of synaptic connections, while, at the same time, increasing functional specificity. Nonetheless, given the proximity of synaptic neighbours, these adaptations are unlikely to compromise functionality to any great degree. Now go to YouTube and search for videos of tardigrades operating in their environment. Here are a few examples: https://youtu.be/bVDtzHM2-QQ https://youtu.be/bVDtzHM2-QQ https://youtu.be/kux1j1ccsgg https://youtu.be/kux1j1ccsgg https://youtu.be/slYQTMUz62s https://youtu.be/slYQTMUz62s I'm blown away by the complexity of their interaction with the environment and the stark simplicity of their neurological wiring relative to anything else that I can think of. For me it also raises the question of whether they have any subjective experience approximating what we describe as consciousness, or if the entirety of their life is just a long form electro-chemical reaction of deeply nested feedback loops programmed into ~55 million base pairs. Either way it’s simultaneously amazing and humbling. 1 - https://bib-pubdb1.desy.de/record/401705/files/Martin_et_al.pdf https://bib-pubdb1.desy.de/record/401705/files/Martin_et_al.... 2 - https://benthamopen.com/contents/pdf/TOZJ/TOZJ-3-1.pdf https://benthamopen.com/contents/pdf/TOZJ/TOZJ-3-1.pdf
- crehn 5y ago
  For contrast, ants have around a quarter million neurons.
  - jcims 5y ago
    We have mud dauber wasps around the house. I can't find a good reference for neuron count...the only one I see is for super tiny parasitic wasps which I can't imagine is accurate. Lets assume they are on the order of honey bees at 500k-1M neurons. This past fall I saw one on the ceiling of my front porch. It had a rear leg pinched between the soffit and the edge of a can light. It was pretty obviously struggling, pulling away with its remaining legs and every now and then buzzing its wings. It was interesting but kind of a dumb 'more powah' response that could be the result of a biological integrator of some form. I then saw one of the most remarkable things that I've personally witnessed in nature. Another wasp of the same type was randomly flying by, about 6" below the level of the ceiling and along a path that would have brought it no closer than a foot away from the stuck wasp. After flying past the stuck wasp, it took a hard right, circled around and landed near the stuck one. It then proceeded to walk up, grab the stuck ankle (?) of the other wasp and help it tug. They both worked on it for a few seconds, broke the first wasp free (not sure if the foot was still intact), then they both flew away in different directions. I can build a mental model of a biological automaton lacing together finely tuned feedback loops that cause it to 'act' in a way that supports itself. Extending that to a point where it appears to identify, empathize, re-plan, solve a physical problem then resume prior plan starts to stretch my ability to imagine without some kind of subjective consciousness backing it all.
davidkuennen 5y ago
"A more recent preprint published this month on the physics arXiv claims—controversially, it must be said—that frozen tardigrades can achieve a state of "temporary quantum entanglement" when incorporated into a superconducting qubit (quantum computing's basic unit of information), and then be revived again." It's amazing what those little creatures are going through since we discovered them.

160 points by _Microft 5y ago

Help me out here: > the size of tardigrades (which are only about 0.02 inches long) > the creature's movement resembles that of insects 500,000 times their size 0.02 inches x 500,000 = 10,000 inches or 833 feet. Where does one find insects 800+ feet long? Or rather, how does one stay the heck away from them?

shard 5y ago
Length is one measure of size, but it may be volume that the title is referring to. So assuming a .02" sphere, 500k times would be about a 1.6" sphere, if my math is correct.
Out_of_Characte 5y ago
They define size as volume or weight rather than length, which makes sense, im 180cm long, an elephant is ~4 meters, making it twice as tall. but its weight can be 6000kg which is a factor of 100 larger than my measely 60kg. Volume grows at ^3 with increase in cubic length.

twirlock 5y ago

dang 5y ago

Recent and related: Tardigrades Walk - https://news.ycombinator.com/item?id=28380188 https://news.ycombinator.com/item?id=28380188 - Sept 2021 (29 comments) Entanglement between superconducting qubits and a tardigrade - https://news.ycombinator.com/item?id=29580686 https://news.ycombinator.com/item?id=29580686 - Dec 2021 (111 comments)

hetspookjee 5y ago
Thank you for linking those threads as the latter one was a thrill to read: both the thread as the paper.

tiahura 5y ago

“The team was surprised to note that the water bears did not have distinct gaits for each speed, like horses as they transition from a walk to a gallop. Rather, their locomotion closely resembled that of insects and arthropods, scurrying along faster and faster with no change to the basic step pattern.” So they expected them to walk like horses and not insects? That seems odd.

steve_adams_86 5y ago
I don’t know if it was an expectation so much as an observation which was then put into comparison to help explain it.
clairity 5y ago
what's more odd is that "...locomotion closely resembled that of insects and arthropods, scurrying along faster and faster with no change to the basic step pattern" is completely wrong. many insects and arthropods change gaits/step patterns with speed. it's practically required, as you get beyond optimal energetics pretty quickly (like being stuck in the wrong gear too long on a bike). cockroaches, for instance, only use their back 4 legs when 'running', and will use only their back 2 legs when all out 'sprinting'. we humans start jogging and then running as speed increases for the same reason, it's not energetically efficient to just 'walk faster'.
jakear 5y ago
Probably not as easy to secure additional funding/headlines when the tagline is “tardigrades move in the simplest conceivable manner, much like other simple creatures”.
ru552 5y ago
I think they were just trying to express that animals generally change their gait as they increase speed. These specific animals do not, which is akin to insects.

sebow 5y ago

This has been known for a while now, but it's definitely still fascinating.Also it reminds me of another similar comparison: humans "walk" like proteins on microtubes.

1024core 5y ago

> "Other times, they’d see something they like and run towards it.” Can tardigrades really "see" in the traditional sense? Can they make out shapes, etc.? Do they have photo receptors plugged into the brain?

jbotz 5y ago
They can't "really see"... they have eyespots with just a handful of light-sensitive cells and no lenses, so it's just gradients of light and dark. But they have other senses and I think the word "see" was metaphorical here, meaning they sensed the presence of an attractive stimulus. In some ways the real meaning of "see" doesn't depend on optics, you see?
- throwamon 5y ago
  According to a video from another comment, each eyespot is a single cell. https://www.youtube.com/watch?v=kux1j1ccsgg https://www.youtube.com/watch?v=kux1j1ccsgg
- scotty79 5y ago
  I don't know. They seem to be able to squeeze out a lot of funtionality out of very limited numbers of cells. I wouldn't be surprised if at some point it was discovered that their light sensitive cells slosh around the cytoplasm inside the roughly spherical cell wall turning it into ad-hoc lenses even if for a brief moment. It still might be enough to get light intensity in a specific direction.

jcims 5y ago

With a few minutes of googling the only reference i can find says that Tardigrades have approximately 200 neurons in their brains [1] and their dry weight is on the order of one microgram [2]. They also have a lower count of synaptic connections (from the same paper): >Thus, miniaturisation of the tardigrade nervous system is achieved largely by reducing cell numbers, neuropil branches and the number of synaptic connections, while, at the same time, increasing functional specificity. Nonetheless, given the proximity of synaptic neighbours, these adaptations are unlikely to compromise functionality to any great degree. Now go to YouTube and search for videos of tardigrades operating in their environment. Here are a few examples: https://youtu.be/bVDtzHM2-QQ https://youtu.be/bVDtzHM2-QQ https://youtu.be/kux1j1ccsgg https://youtu.be/kux1j1ccsgg https://youtu.be/slYQTMUz62s https://youtu.be/slYQTMUz62s I'm blown away by the complexity of their interaction with the environment and the stark simplicity of their neurological wiring relative to anything else that I can think of. For me it also raises the question of whether they have any subjective experience approximating what we describe as consciousness, or if the entirety of their life is just a long form electro-chemical reaction of deeply nested feedback loops programmed into ~55 million base pairs. Either way it’s simultaneously amazing and humbling. 1 - https://bib-pubdb1.desy.de/record/401705/files/Martin_et_al.pdf https://bib-pubdb1.desy.de/record/401705/files/Martin_et_al.... 2 - https://benthamopen.com/contents/pdf/TOZJ/TOZJ-3-1.pdf https://benthamopen.com/contents/pdf/TOZJ/TOZJ-3-1.pdf

crehn 5y ago
For contrast, ants have around a quarter million neurons.
- jcims 5y ago
  We have mud dauber wasps around the house. I can't find a good reference for neuron count...the only one I see is for super tiny parasitic wasps which I can't imagine is accurate. Lets assume they are on the order of honey bees at 500k-1M neurons. This past fall I saw one on the ceiling of my front porch. It had a rear leg pinched between the soffit and the edge of a can light. It was pretty obviously struggling, pulling away with its remaining legs and every now and then buzzing its wings. It was interesting but kind of a dumb 'more powah' response that could be the result of a biological integrator of some form. I then saw one of the most remarkable things that I've personally witnessed in nature. Another wasp of the same type was randomly flying by, about 6" below the level of the ceiling and along a path that would have brought it no closer than a foot away from the stuck wasp. After flying past the stuck wasp, it took a hard right, circled around and landed near the stuck one. It then proceeded to walk up, grab the stuck ankle (?) of the other wasp and help it tug. They both worked on it for a few seconds, broke the first wasp free (not sure if the foot was still intact), then they both flew away in different directions. I can build a mental model of a biological automaton lacing together finely tuned feedback loops that cause it to 'act' in a way that supports itself. Extending that to a point where it appears to identify, empathize, re-plan, solve a physical problem then resume prior plan starts to stretch my ability to imagine without some kind of subjective consciousness backing it all.

davidkuennen 5y ago

"A more recent preprint published this month on the physics arXiv claims—controversially, it must be said—that frozen tardigrades can achieve a state of "temporary quantum entanglement" when incorporated into a superconducting qubit (quantum computing's basic unit of information), and then be revived again." It's amazing what those little creatures are going through since we discovered them.