They consist of a ring of mammoth 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 used to construct the [very same] features" (see).
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" (see).
A recent research on a freshly dug out structure, though, challenges that view in a way supporting alternative hypothesis, like that that sees the mammoth-bones circles being "monumental architecture or possible ceremonial features" (see).
The studied mammoth-bones circle with a diameter of 12.5 meters (41 feet), indeed, has no obvious entrance and shows a "relative scarcity of minute debitage [that] seems incongruous for a putative dwelling" (see).
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) (see).
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)|