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Giant 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

by bj85 2y ago

Giant 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 ago
Good question, species do not put that much compulsive effort into preemptive escape without cause.
- IncreasePosts 2y ago
  Maybe humans just used the claws of dead giant sloths to carve the caves for their own purposes.
  - metalmangler 2y ago
    as 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 ago
    Tunels 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.
    - ruleryak 2y ago
      the sandstone formation is 100 million years old, not the tunnels
    - ainiriand 2y ago
      No, what is 100 million years old is the rock layer. The tunnels are `recent`.
    - tangus 2y ago
      Just in time to kill the giants sloths?
- Retric 2y ago
  Thermal 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 ago
  Thank you for the aquatic sloth link, that's so cool!
- beambot 2y ago
  Manatees and dugongs feel like "whale-like sloths", though I have no idea if they're taxonomically related
  - Qem 2y ago
    They are more closely related to elephants.
adolph 2y ago
The 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 ago
  https://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 ago
    My 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 ago
Glossotherium 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...

by bj85 2y ago

tejtm 2y ago

Good question, species do not put that much compulsive effort into preemptive escape without cause.

IncreasePosts 2y ago
Maybe humans just used the claws of dead giant sloths to carve the caves for their own purposes.
- metalmangler 2y ago
  as 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 ago
  Tunels 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.
  - ruleryak 2y ago
    the sandstone formation is 100 million years old, not the tunnels
  - ainiriand 2y ago
    No, what is 100 million years old is the rock layer. The tunnels are `recent`.
  - tangus 2y ago
    Just in time to kill the giants sloths?
Retric 2y ago
Thermal 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 ago
Thank you for the aquatic sloth link, that's so cool!
beambot 2y ago
Manatees and dugongs feel like "whale-like sloths", though I have no idea if they're taxonomically related
- Qem 2y ago
  They are more closely related to elephants.

adolph 2y ago

The 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 ago
https://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 ago
  My 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 ago

Glossotherium 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...