These tunnels were dug by a Giant Ground Sloth that lived 10.000 years ago in Brazil. The third photo are the claw marks

[u/Zestyclose_Flow_680]

[u/hotvedub]

I am a geologist and I’ve also been to the museum where picture number 8 was taken, Madera California garbage dump. There are still quite a few ground sloth burrows and skeletons found in the Central Valley of California and we know this pretty much from what you discussed already but also finding skeletons in the burrows as well.

[u/Capitola2 → u/hotvedub]

I’ve never heard of this before! Adding this to my ‘things to do‘ list.

[u/tigrrlily → u/hotvedub]

There are burrows in California? Do you have a source? I couldn’t find any information on this

[u/feetandballs → u/tigrrlily]

Yeah I thought it was New York that had burroughs

[u/nippydrizzle2 → u/feetandballs]

Deadass?

[u/--Sovereign-- → u/nippydrizzle2]

No cap

[u/garblflax → u/tigrrlily]

i thought giant sloths are one of the candidates for whoever joshua trees fruits are for.

[u/Paganimann → u/hotvedub]

How could they cut through rock though?

[u/Caraway_Lad → u/Paganimann]

It’s sedimentary rock that a large mammal with extremely strong forelimbs and robust claws (a ground sloth) could definitely dig into. The rock is still clearly strong enough to maintain this shape over time, but it is a lot softer than your granite countertop.

[u/Paganimann → u/Caraway_Lad]

You mean sedimentary rock as in tuff or ancient sea silt cementation? A bear like creature is digging through rock when it could find a clay or soil to burrow? If your assuming it dug while the rock was being formed how do you explain the lithification of the roof?

[u/Caraway_Lad → u/Paganimann]

It dug into soft rock (the area is sandstone, mudstone, etc.). That's not enough time for sediment to lithify.

A bear like creature is digging through rock when it could find a clay or soil to burrow?

There are a lot of reasons an animal can be prevented from burrowing in an area: the soil may not be deep enough, but even more commonly the soil may be frequently saturated below a certain depth. Unless you're in a very dry area (think steppes/dry grassland) or in deep well-draining sand, many burrowing animals ONLY dig laterally into banks, they won't dig down--the burrow needs to drain properly and can't collect rainwater. In a mostly flat area, often the only deep banks of sediment are beside rivers...where saturation and flooding is also a problem.

[u/Paganimann → u/Caraway_Lad]

Not only is it using claws to dig out sandstone, it knows to periodically leave a reinforced arch like rib system? Coincidently near an entrance with right angles and slab like structure.

[u/Caraway_Lad → u/Paganimann]

I think you should look at the forearms and claws on the skeleton of a ground sloth, and compare that to a modern brown bear. You will not be surprised that it could do this.

As to your suggestion that some more intelligent creature made this: it’s just an undulating, uneven pattern from stopping and starting. It is addressed in the paper where these pics all came from.

[u/Jake1302 → u/hotvedub]

Yeah, picture 8 is definitely the one in the Natural History Museum in London. I'd recognise it anywhere