The symbiotic relationship between the Nenets people of the Siberian arctic and their reindeer goes back centuries. This nomadic tribe acts as guardians and protectors of Russia's domestic caribou, accompanying hundreds of thousands of them on their annual migration across some of the world's harshest climates. In return, the reindeer not only clothe the tribe, but also provide nourishment and a livelihood.

Once a year, typically in August, the Nenets people gather together in Siberia's arctic region to celebrate Reindeer Herder's Day, which honors the trade and the animal. Festivities include wresting competitions and reindeer races, as well as feasts and traditional dances. Below, a look at this ancient culture through recent Reindeer Herder's Day celebrations.

A herder works with reindeer at a campground in Nenets Autonomous Area, in northern Russia. | (REUTERS/Sergei Karpukhin)

A reindeer breeder races in a competition in Lovozero settlement, Russia. | (Fedoseyev Lev/ITAR-TASS Photo/Corbis)

The son of a local herder throws a lasso in Nenets Autonomous Area. | (REUTERS/Sergei Karpukhin)

A Nenets woman rides in a sleigh in the tundra after the Reindeer Herder's Day in Nadym, Russia. | (AP Photo/Dmitry Lovetsky)

Nenets children attend the Reindeer Herder's Day holiday in Nadym. | (AP Photo/Dmitry Lovetsky)

A Nenets man rides a reindeer sledge during a competition to mark Reindeer Day. | (REUTERS/Sergei Karpukhin)

Crafts made from reindeer fur, as well as fish, are for sale in the Nenets Autonomous Area. | (Strunin Anatoly/ITAR-TASS Photo/Corbis)

A herder sits on a reindeer sleigh in Nadym. | (AP Photo/Dmitry Lovetsky)

A Nenets woman walks by chums, the temporary huts erected during their journeys, in Nadym. | (AP Photo/Dmitry Lovetsky)

Herders work with reindeer at a campground northeast of Naryan-Mar, Russia. | (REUTERS/Sergei Karpukhin)