What know you of the devil’s corkscrew? (Thread).

During excavation works in Sioux County, Nebraska, palaeontologist Erwin Barbour found spiral structures that went roughly 3 metres into the ground. Neither he nor the scientific community of the time had ever seen the like.

He couldn’t work it out. The surrounding area’s material had been laid down in a freshwater lake 20 million years before, so were they giant sponges? Or vegetation?

What was even more bizarre is that at the base of these huge screws were offshoots. This wasn’t your typical design of a plant. The jury was out in regards to what the hell they were. Here are some examples from @MorrillHallUNL

The archaeology around the spirals were more connected to grassland than a lake, so clearly weren’t contemporary to its foundation millions of years before. Years later someone had the idea to excavate within the spirals themselves to analyse their composition. Well. Looky here.

In them they found the remains of a rodent, which, as research down the years revealed, excavated these burrows with their teeth. https://hoopermuseum.earthsci.carleton.ca/Burrowsite/fossil4.htm

The bones and teeth marks were analysed to be that of paleocastor, an extinct relative of another rodent that makes impressive architectural pieces: the beaver. From 1891/2 it wasn’t until 1977 that this was worked out!

The corkscrews are actually trace fossils - which I’m completely infatuated with - the discipline is called ichnology. Handy little guide here: https://blogs.scientificamerican.com/history-of-geology/on-the-track-of-ichnology/

So why did they dig these elaborate coils? No animal digs a shaft because they’d get stuck. Scientists think that the screw allowed easy ingress and egress, as well as allowing multiple burrows to occur in a small area. Safety in numbers and a sense of community, maybe?

What is likely is that the reason for it was to keep cool. The coils also slowed air flow which, when this creature was alive, would have been handy as Nebraska as a grassland would have had sandstorms - which would have filled their burrows if they were simple shafts.

The softer sand around the coils eroded away as time marched on past their extinction, whilst built up sediment created perfect casts of these ancient hidey holes. And it’s these hidey holes that give us a wonderful glimpse into this bizarre relative of the modern beaver.

Loads of sources have more information like @SmithsonianMag but @EonsShow is what told me about this - wonderful glimpses into the life of this ancient rodent and more accessible science videos too. Trace fossils! Just as good as bone and stuff!