The Deer Mother, aka the Antlered Mother, guides us through the nights of Solstice, carrying the light in her horns. Unlike the male reindeer, she keeps her antlers throughout the winter. She is the source of life, the keeper of the pathways.
To the people of the far North, reindeer (aka caribou in North America) were the source of life and sustenance in winter: meat, milk, hides for clothing and shelter.
And for some, the Old Antlered One is an aspect of An Cailleach, the Hag of Winter, the Mother of the Herd.