[HN Gopher] Scientists Figured Out How Eels Reproduce (2022)
___________________________________________________________________
Scientists Figured Out How Eels Reproduce (2022)
Author : thunderbong
Score : 106 points
Date : 2026-04-01 22:33 UTC (4 days ago)
(HTM) web link (www.intelligentliving.co)
(TXT) w3m dump (www.intelligentliving.co)
| rbanffy wrote:
| The click bait version adds "and it's electrifying".
| arduanika wrote:
| I'm just glad that somebody solved this very slippery problem.
| adamlgerber wrote:
| everyone here is talking about eels but i prefer icktok
| wood_spirit wrote:
| I remember being fascinated by animals as a kid and the mystery
| of where eels went was one of the big unsolved puzzles I remember
| hearing about.
|
| Much more recently I heard on QI about how medieval people, not
| knowing about migration, believed, through a lot of leaps, that
| it was ok to eat barnacle geese at lent. Worth investigating if
| you are curious :)
| bcraven wrote:
| This is a good video on that medieval belief:
|
| Medieval Science was Baffled by Birds - CuriousCabinet123
|
| https://youtu.be/vgFj-MMTqIc
| HiPhish wrote:
| I find it very hard to believe that people in the middle ages
| (or before or after) looked at birds and actually thought that
| they really spawned from trees or barnacles. After all, birds
| can fly, you observe large flocks of birds in the sky right
| before they vanish, you know that there are warmer regions in
| the south, so it's not a big stretch to imagine that birds
| could perhaps migrate southwards. You cannot prove it, but it's
| a good enough guess.
|
| I think illustrations or stories from the middle ages are to be
| taken as symbolic or allegorical rather than factual like a
| biology book would be today. They wrote down a story not
| because they necessarily believed it be factually true, but
| because it taught a different kind of truth. For example, no
| one has ever believed that Red Riding Hood actually happened or
| that you can cut open a wolf's stomach to pull out a living
| person.
| throwup238 wrote:
| _> You cannot prove it, but it 's a good enough guess._
|
| You can guess that _now_ in the 21st century, but we 're
| talking about illiterate peasants who never traveled past
| their nearest market center. It's naive to assume we can even
| possibly empathize with their epistemological outlook.
|
| For example, just look at the medieval sources about barnacle
| geese from the 13th century (from the _educated_ class):
|
| _> Barliates, as Aristotle says, grow from wood, and are
| birds which the common people call 'barnesques', having a
| similar nature._ [1] (I chose a short quote to make a point
| but please read the rest of the source, it's hardly an
| allegorical text)
|
| They didn't have the concept of falsifiability or anything
| even remotely resembling the scientific process (or critical
| thinking, for the most part). The literate were obsessed with
| the classics and just took Aristotles and Ptolemy's word for
| everything, until Copernicus and Kepler had their way.
| Anything resembling scientific knowledge filtered down to the
| peasants or came from old wives tails entirely.
|
| Even now with almost universal literacy we have a significant
| fraction (if not majority) of the population believing in
| ridiculously stupid nonsense like astrology. I don't find it
| hard to believe that people thought that geese's life cycle
| included barnacles.
|
| [1] https://www.medievalbestiary.bestiary.ca/beasts/beastsour
| ce1...
| B1FF_PSUVM wrote:
| > old wives tails
|
| Please, can I have that for my typo collection?
| dudefeliciano wrote:
| It took until the 1800s for us to finally understand where
| the hell birds go in the winter, we had all kinds of crazy
| theories before then. We finally realized birds migrate to
| Africa, with proof, when a stork arrived in Germany after
| surviving being shot by an arrow in Africa.
|
| https://en.wikipedia.org/wiki/Pfeilstorch
| dudefeliciano wrote:
| > it was ok to eat barnacle geese at lent.
|
| I think that was just a way to ethically cheat the fast...In
| southern Germany they got around it by wrapping the meat in a
| dumpling (Maultaschen), so that god wouldn't notice: "The
| Swabian German nickname for the dish, Herrgottsbescheisserle,
| means "small God-cheaters""
|
| https://en.wikipedia.org/wiki/Maultasche#History
|
| EDIT: just remembered another similar cheat, where beavers were
| defined as fish, allowed to be eaten at lent.
| mananaysiempre wrote:
| > Much more recently I heard on QI about how medieval people,
| not knowing about migration, believed, through a lot of leaps,
| that it was ok to eat barnacle geese at lent.
|
| There's a similar story about how rabbits in Japanese use the
| classifier Yu ( _-wa_ , "wing") normally utilized for birds,
| instead of the Pi ( _-hiki_ ) you'd expect for small animals,
| because Buddhist monks really wanted to eat them and thus
| declared their ears to be wings. I don't know how historically
| accurate that is. (I'm also assuming this has to come from
| Chinese and thus likely also has a counterpart in Korean, but
| can't prove that with a cursory look through Wiktionary.)
| DeanStevenson wrote:
| Fascinating how certain animals have evolved with complex
| migration patterns to breeding grounds. And unfortunate that 95%
| of the population has already collapsed.
|
| Makes me wonder what the world was like before this last great
| extinction.
| Nzen wrote:
| tl;dr Eels have a long lifecycle with several stages. They do
| not develop sexual organs until late in their life, when they
| migrate back to the Saragossa Sea. This meant earlier autopsies
| of eels revealed no sexual organs, even though scientists could
| provoke them with hormone therapy. So, a team lead by Jose
| Azevedo tagged female eels in the Azores in 2018, and tracked
| them via satellite [0].
|
| [0] https://www.nature.com/articles/s41598-022-19248-8
|
| I sometimes think about the selection pressures that lead to
| complex life cycles, like fig wasps. I find myself thinking
| about it naively, like one existed and the other grew into the
| niche. But, realistically, everything is changing (slowly) all
| the time. I just notice it for, say, influenza because their
| cycle time is so short.
| jfengel wrote:
| The important part of the story is that it took so long.
| People actively searched for an answer for thousands of
| years.
|
| The answer itself is interesting, but more remarkable to me
| is how doggedly people pursued it for so long. It seems so
| basic that they must reproduce the way other vertebrates do,
| and yet the lack of apparent organs was baffling.
| mosaibah wrote:
| Aristotle spent serious time on this and concluded eels
| spontaneously generated from mud, that's not a knock on him, you
| genuinely cannot find reproductive organs in a wild eel because
| they don't develop until the final migration, it took satellite
| tagging in 2018 to actually confirm what was happening. A 2,300
| year old mystery closed by a GPS tracker is a good reminder that
| some problems just had to wait for the right instrument
| jfengel wrote:
| That is a very big deal observation. Philosophers of science
| have a concept called "theory ladenness". Until the right tool
| arrives you may not even be able to formulate the question, and
| you don't know it. You keep dancing around versions of the
| wrong question.
|
| The history of heat versus temperature is quite enlightening.
| The absence of thermometers means you have a hard time
| conceiving of heat capacity. They knew that phlogiston wasn't
| right but all of their experiments kept assuming it was
| measurable. Same with mass versus weight; the difference isn't
| hard to measure once it occurs to you to measure it.
|
| These can be great aha moments in the history of science. It's
| both daunting and inspiring.
| nfw2 wrote:
| I think it's reasonable to knock on someone for concluding a
| wildly incorrect theory (eg generating out of mud) even when
| lacking evidence pointing to the correct answer. Aristotle did
| this a lot. The correct position in these scenarios is one of
| uncertainty.
| gcanyon wrote:
| "figured out how" seems a little strong, when:
|
| > questions remain about the timing and navigation of the eels
| across thousands of kilometers of open water
| dundarious wrote:
| In the satellite tracking experiment, I wonder how they sexed the
| eels to determine they were female before tagging, given the lack
| of primary sex organs at that time. Are there obvious secondary
| characteristics like size?
|
| > The researchers behind this recent discovery used satellite
| tags to follow 21 female European eels as they navigated the
| final phase of their incredible journey southwest from the
| Azores, the volcanic archipelago of the North Atlantic Ocean west
| of Portugal.
| joss82 wrote:
| They swabbed them and sequenced their DNA.
| dundarious wrote:
| Thank you, I forgot that's cheap enough these days.
| tsimionescu wrote:
| That just moves the question to how they figured out the
| genetic sex determination system of eels, or even how they
| figured out that sex is genetically determined in eels (and
| is it? many vertebrates don't have genetically determined
| sex).
___________________________________________________________________
(page generated 2026-04-05 23:01 UTC)