The mysterious origin of Nebraska's 'Devils Corkscrews'

Millions of years ago, the remote badlands of Nebraska were home to an ancient creature, the Palaeocastor, a small, now-extinct beaver. These creatures left behind tall, spiral structures known locally as Devil’s Corkscrews. But what were they used for?

The Palaeocastor is a small, now-extinct beaver that lived during the late Oligocene period, about 23 million years ago. It was much smaller than today's beavers, being about the size of today's prairie dog. These rodents provided the final clue to a mystery that has confounded scientists for nearly a century.
A rancher, James Cook found devil’s corkscrews on his property along the Niobrara River in Sioux County, Nebraska in1891. He then alerted paleontologist Erwin H. Barbour. In 1892, after examining the spirals, Barbour named them Daimonelix (Greek for “devil’s screw,” often spelled Daemonelix). Barbour collected dozens of samples - noting there was nothing in the fossil record at that time that looked like them.
At first, Barbour surmised the strange corkscrew-shaped fossils were the remains of giant freshwater sponges, but then decided they were the remains of plants, possibly root systems, because he had discovered plant tissues inside the helices. Barbour's identification was influenced by the surroundings where the "screws" were found.
Daemonelix burrows in the Miocene of Nebraska  USA. (original vintage photo owned by the University ...
Daemonelix burrows in the Miocene of Nebraska, USA. (original vintage photo owned by the University of Nebraska.
James St. John
The deposits in which they occur were laid down in immense freshwater lakes in the Miocene Epoch, 20 million years ago. Also for a while, people tended to believe the spiral forms are a curious type of extinct vegetation. It is well known today that millions of years ago, what is now the Great Plains was once underwater.
By 1893, other paleontologists started weighing in on Barbour's find - including the legendary American vertebrate paleontologist Edward Drinker Cope. He rejected Barbour’s interpretation of the fossils, noting that “the most probable explanation of these objects seems to be that they are the casts of the burrows of some large rodent," according to the Smithsonian. Much later, his assumption would prove to be correct.
Palaeocastor magnus Romer & McCormack  1928. The skull is at the lower left. The elongated black str...
Palaeocastor magnus Romer & McCormack, 1928. The skull is at the lower left. The elongated black structures there are incisor teeth.
James St. John (CC BY 2.0)
Finding extinct rodent’s bones
It was really too much of a coincidence, but researchers began finding little fossilized rodent bones inside the spirals, and by the end of 1893, they proposed a new theory - The spirals themselves weren’t the remains of organisms - but were the remnants of intricate spiral burrows dug by the rodents found entombed in the base.
It took until 1905 before scientists were able to prove this theory was correct. By then, they had found scratch marks on the inside of the spirals indicating that they had been clawed out of moist soil. Austrian paleontologist Theodor Fuchs, an authority on trace fossils, drew his own conclusion, saying, “thus we are justified in viewing these strange fossils as really nothing more than the underground homes of Miocene rodents, probably related to Geomys [pocket gophers].”
Palaeocastor and burrow in National Museum of Natural History.
Palaeocastor and burrow in National Museum of Natural History.
Well, Barbour would not go down without a fight and published a critique of Fuchs’s analysis in 1894. Barbour noted that “Dr. Fuchs’ gopher is left to burrow and build its nest of dry hay in one or two hundred fathoms of Miocene water.” (Fuchs had doubted that the surrounding rocks were lake deposits and interpreted the plant remains found by Barbour as hay stored by the burrow-maker.)
About the only part of the Devil's Corkscrew mystery anyone had solved was the spirals were once animal homes. And that was the leading hypothesis until 1977. Everyone had overlooked the true creators of the unusual spirals. Experts found that Palaeocastor was the real architect of these trace fossils after noting that the formations bore the beaver's signature teeth marks.
Paleocastor was an ancient beaver whose life style has been compared with modern prairie dogs. The P...
Paleocastor was an ancient beaver whose life style has been compared with modern prairie dogs. The Paleocastor was terrestrial, i.e. lived on (and in) land, instead of mostly in water, as today's beavers do.
Nobu Tamura -2008
Trace fossils (otherwise known as ichnofossils) are an echo of ancient life, providing evidence of animal activity in the past. While not a normal fossil that shows us the animal or plant in death, a trace fossil shows us how the animal lived. Trace fossils include fossilized animal burrows, footprints, tracks, trails, nests, eggs, and feces.
The research on Daimonelix, published in 1977, painted a completely new picture of these strange spiral structures and their origin.