Waldemar Bogoras
Sons of the Mammoth
From the dustjacket:

In the days when the world was young, Yarry, a member of the tribe that held itself to be descended from the mammoth, profaned against the tribal mysteries and was driven out to the primeval wilderness, first taking his mate out of the camp of the women.

Autumn came, and the time of the mammoth hunt. There appeared in the hills a vast monster called the Rek, bringing fear and destruction. For this the tribal wizards blamed Yarry and his woman.

There follows a series of weird and hair-raising events, ending in a magnificent denouement.

Waldemar Bogoras, who besides being an internationally famous anthropologist is also famous in Russia as a novelist, has written this brilliant story of prehistoric man, interpreting the strange drawings of mammoths done ages ago on the walls of caves and still found all over Europe and Asia, infusing the breath of life into the lore of the scholar's study and the dust of the museum.

"Sons of the Mammoth" is not only a story of tremendous dramatic force, but a scientific reconstruction of the Stone Age and its people — how they lived and hunted, waged war and made love, how they celebrated their joys and worshipped their grotesque gods.