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Who carved South America's mysterious ancient tunnels? [pdf]
- ggm 2y agoBruce Chatwin mentions the tunnels and sloths in his book "in Patagonia" 1977
- stargrazer 2y agoI wish there were more pictures.
- bj85 2y agoGiant sloths was not really on my list of expected answers but "One species, Glossotherium robustum, a South American sloth that lived between 4 million and 12,500 years ago, reached more than 3 metres in length and weighed up to 1,500 kilograms" But who was really in charge?
- tejtm 2y agoGood question, species do not put that much compulsive effort into preemptive escape without cause.
- IncreasePosts 2y agoMaybe humans just used the claws of dead giant sloths to carve the caves for their own purposes.
- metalmangler 2y agoas is often the case, one species will make a burro only to have other species take over and modify it, with choice locations, used contiously for several millenia, so an odd scratch here and one there adds up, and we have no other behavioral evidence for this last mega fauna, so who knows? might find more of these in different stages, with perhaps fossil evidence
- gus_massa 2y agoTunels are 100 millions year old. We split from chimps 5 millions years ago. Modern humans are .11 million year old, and we arrived to America .015 million years ago.
- Retric 2y agoThermal regulation is a possibility mentioned outside of predation. Bears aren’t afraid of being eaten, but they still dig dens because they’re warm in the winter.
- Qem 2y ago> Giant sloths was not really on my list of expected answers Despite not looking very alike at the first glance, sloths are grouped together with armadillos in the clade Xenarthra[1]. Both lineages descend from a common ancestor from around the time the dinosaurs went extinct. So it's not that surprising there were burrowing sloths. I guess the burrowing behaviour surely came handy to their shared ancestor by the time the dinosaurs were screwed by the asteroid that carved the Chicxulub crater[2]. What is mind-boggling for me is that once there were aquatic sloths[3]. Some sloths followed the steps from the ancestors of whales and dolphins, and rehearsed a return to sea. Unfortunately that evolutionary experiment was cut short when the gap between south and north america closed, isolating atlantic from pacific oceans and dooming the niche where the critters thrived. Had they persisted, I wonder if by now we could have whale-like sloths (whaloths?). [1] https://en.wikipedia.org/wiki/Xenarthra https://en.wikipedia.org/wiki/Xenarthra [2] https://en.wikipedia.org/wiki/Chicxulub_crater https://en.wikipedia.org/wiki/Chicxulub_crater [3] https://en.wikipedia.org/wiki/Thalassocnus https://en.wikipedia.org/wiki/Thalassocnus
- bloopernova 2y agoThank you for the aquatic sloth link, that's so cool!
- beambot 2y agoManatees and dugongs feel like "whale-like sloths", though I have no idea if they're taxonomically related
- Qem 2y agoThey are more closely related to elephants.
- adolph 2y agoThe giant sloth was the first thing that came to my mind. Nearly every time I'm at the grocery I think about the giant ground sloth theory of avocado evolution: A number of authors, including Connie Barlow in her 2001 book The Ghosts of Evolution, have speculated that the avocado is an "evolutionary anachronism" with megafaunal dispersal syndrome (a concept originally proposed in the 1980s by Paul S. Martin and Daniel H. Janzen), arguing that the avocado likely coevolved dispersal of its large seed by now-extinct megafauna. Barlow proposed that the dispersers included the gomphothere (elephant relative) Cuvieronius, as well as ground sloths, toxodontids, and glyptodonts. The concept of evolutionary anachronisms/megafaunal dispersal syndrome has been criticised by some authors, who note that many large fruit are readily dispersed by non-megafaunal animals, with it being noted that living agoutis disperse avocado seeds, with spectacled bears have also having been observed eating domestic avocados. https://en.wikipedia.org/wiki/Avocado https://en.wikipedia.org/wiki/Avocado
- TaurenHunter 2y agohttps://link.springer.com/article/10.1007/BF02904012 https://link.springer.com/article/10.1007/BF02904012 Early wild avocado seeds were smaller at around 2cm/.8in in diameter.
- gus_massa 2y agoMy aunt has a big avocado tree in the north west of Argentina. The avocato are very small, probably an inch long. They are very tasty, but you must collect a lot of them to prepare a dish.
- tim333 2y agoGlossotherium robustum looks quite chunky. There's a skeleton of one in the Natural History Museum London https://en.wikipedia.org/wiki/Glossotherium https://en.wikipedia.org/wiki/Glossotherium and an artists impression https://static.wikia.nocookie.net/fossil/images/9/95/Reconstruction_of_Glossotherium_robustum_size.png/revision/latest/scale-to-width-down/1000?cb=20240522060510 https://static.wikia.nocookie.net/fossil/images/9/95/Reconst...
- bell-cot 2y ago> The longest described so far is in Pará state in the Amazon region, with combined internal galleries some 1,500 metres long ... I'm not a Mining Engineer, to know when CO2 accumulation would become a problem (if the giant sloths were living in the tunnels). But the effort needed to manually remove the tailings from a tunnel is O(n^2) - because the working face keeps getting further from the exit. So as the article asks - how could the effort needed possibly be worthwhile?
- cess11 2y agoHow would the animal determine that the effort is no longer worthwhile?
- bell-cot 2y agoI don't know. But pretty much every burrowing animal has to decide when the RoI has gotten too low to keep digging.
- goatlover 2y agoDo they use a spreadsheet?
- bell-cot 2y agoNeural network.
- adrianmonk 2y agoNo, a Burroughs mainframe.
- Qem 2y agoIt appears to be combined lenght for the whole tunnel complex. Not 1,500 meters to the nearest exit.
- rdtsc 2y agoDig slightly up so CO2 doesn’t accumulate in low areas and spread the tunnels around like a tree or a mesh? Work with your fellow sloth team, take turns, dilly-dally around. What else would sloths do ;-)
- mmooss 2y agoThe article at its source, Nature, with many more photos and a different title: "Did giant ice age beasts carve these vast caves in South America?" https://www.nature.com/articles/d41586-025-00216-x https://www.nature.com/articles/d41586-025-00216-x
- veunes 2y agoThe sheer size of these tunnels is mind-blowing
- _dain_ 2y agogod I wish I could live in tunnels. like a hobbit. these sloths had it all figured out ...
- Chris2048 2y agoWhat's stoppin' ya?
- fc417fc802 2y agoIn most of the western world it's illegal to excavate any significant volume without a bunch of permitting and oversight. Additional regulations surrounding living spaces. Plus the fact that you don't generally own the volume underneath your lot in the first place. If you make it past all that (regardless of whether you selected the legal or illegal route) there's the expense of doing so safely. Then add on the expense of maintenance (by which I mostly mean water management).
- _dain_ 2y agogovernment, money, local geology.
- lmm 2y agohttps://discover.hubpages.com/living/The-Pitfalls-of-an-Underground-House https://discover.hubpages.com/living/The-Pitfalls-of-an-Unde... gets posted here every so often.
- SamBam 2y agoSo not the Shrike?
- beacon294 2y agoI think they were carved by "the builders"...
- caycep 2y agothe irony is if it was some Stone Age counterpart to Seymour Cray
- driggs 2y agoIndeed, similar megafauna were present in North America as well. The West Virginia state fossil is Megalonyx jeffersonii, a giant ground sloth present until the end of the Pleistocene. They're estimated to have been 10 feet "tall" and to weight roughly a ton. Fossil bones were discovered in Haynes Cave, Monroe County near the present day Virginia border, and the species is named for Thomas Jefferson, who examined bones and authored the paper that identified this genus. (Though the history of exactly which bones he identified is slightly murky.) https://en.wikipedia.org/wiki/Megalonyx https://en.wikipedia.org/wiki/Megalonyx It seems likely that they were using these limestone caves for shelter, though it is also not uncommon for other Pleistocene fossils to be found and preserved in caves after washing in as sediment. I've never seen claw marks on cave walls quite large enough to attribute it to a ground sloth, but there are occasionally very large claw marks on cave walls... and I wouldn't want to be trapped in the dark with whatever creature left them behind.
- emilfihlman 2y agoSince no one has said, but I strongly feel like it should be said and it's so great and positive abd triggers many memories. Secret tunnel!
- zkmon 2y agoCarving could have been done by natural processes, instead of creatures? Many large caves are created by simple process of chemical reactions and water flow over time. Any scratches on the surface could be from creatures.
- veunes 2y agoFrom what I've read, these burrows have distinct claw marks ("claw-like markings on the walls") and structural patterns that don't match typical natural cave formation processes
- perlcommunity 2y agookay badger moles
- whatamidoingyo 2y agoI visited MOAS in Daytona last week, and learned about the ground sloth for the first time in my life. Fascinating. I thought I knew just about every animal to have lived on earth, but I was so wrong. Curious what other creatures like this I don't know about.