There are shaggy-dog stories and then there are shaggy-mammoth stories. “10,000 B.C.” is a pachyderm-sized tall tale of prehistoric ardor and tribal warfare directed on an epic scale by Roland Emmerich, who subjected New York to an instant ice age in “The Day After Tomorrow.” Turning his attention to the day before yesterday, he feels no greater obligation to realism, spinning a yarn that owes more to Edgar Rice Burroughs than anthropology.

The scattered narrative is explained on the fly by a gabby elder, the Hamburger Helper of storytelling. Speaking in the “And lo, it came to pass” school of voiceovers, he guides us through the scenic but underdramatized film.

When a clan of northern mammoth hunters holds its seasonal mighty warrior competition, self-doubting D’Leh (Steven Strait) wins by default. Tangled in the net and dragged along to the creature’s semi-accidental death, he accepts credit for the kill because it entitles him to claim his childhood love Evolet (Camilla Belle) as his mate.

But Old Mother, a wise woman with so many trinkets braided in her hair that she looks like a wind chime, foresees doom. A thundering pack of “four-legged demons” on horseback sacks the village for slaves, carrying off Evolet among their prisoners. With a small band of spear-carriers, D’Leh sets off across uncharted mountains and deserts to free his people. Evolet, sporting the kind of twine-and-bone ritual bracelets popular two years ago at Abercrombie and Fitch, drops pieces in a trail for D’Leh to follow across the trackless wastes, a primitive form of GPS tracking system.

The film was handsomely shot in exotic locations, and its budget, reportedly well north of $100 million, bought a lot of impressive special effects. But in the real world of heroic historical loincloth adventures, “10,000” is much less than “300.”