They consist of a ring of mammoths' bones with a diameter of various meters usually surrounded by "a series of large pits" thought to have been used for "the storage of food or bone fuel, rubbish disposal or simply as quarries for loess [a wind-created silt like sediment] used to construct the [very same] features" (P).
The structures are commonly reckoned as "to be the remains of dwellings that offered shelter during long, full glacial winter seasons or possibly year round" (P).
A recent research on a freshly dug out structure, though, challenges that view in a way supporting alternative hypothesis, like that which sees the mammoth-bones circles being "monumental architecture or possible ceremonial features" (P).
The studied mammoth-bones circle with a diameter of 12.5 meters (41 feet), indeed, has no obvious entrance and shows a characteristic that "seems incongruous for a putative dwelling" (P): the "relative scarcity of minute debitage" (P), namely the production waste created during the making of tools from stones and rocks.
The feature is located at the already famous (for this kind of structures) Kostenki 11 site (aka Anosovka 2) which is close to the Don River, near the city of Voronezh, in the European south-western Russia (51°23′08′′ north, 39°03′05′′ east) (P).
Said that, dear reader, this dumb blog has its own hypotesis about how and why the mammoth-bones circles have been made by humans. See the following cartoon.
|Two hunters-gatherers and a circle of mommoth-bones (by @sciencemug)|
[Meat pic by Clker-Free-Vector-Images is under Pixabay Licence (source Pixabay); adapted by @sciencemug]
Pryor,A.J.E., Beresford-Jones, D.G., Dudin, A.E., Ikonnikova, E.M., J.F., Hoffecker, and Gamble ,C. (2020). The chronology and function of a new circular mammoth-bone structure at Kostenki 11 | Antiquity | Cambridge Core 94,323-341