During the golden Viking Age Berzerkers were fierce warriors who fought without restraint in battle. A Berzeker could be identified by the serkr, a shirt or coat, made from the pelt of a bear (ber). They fought in frenzied states of fury that were often worked up by acts against their honor or, as some historians believe, by certain foods. 

The Ulfhesnar are the lupine equalvient to the Berzerkers, who wore a wolf’s pelt instead of a bear’s in battle (as seen in the second image). 

Beowulf is thought to have been a Bezerker because of the bear pelt he wares during his battles in the epic. 

Skald’s, or poets such as Snorri Sturluson, describes Berzerkers as high warrior heroes in his Ynglinga Saga. circa 1225.

However throughout much of the early sagas, Berzerkers were portrayed as bullies who raided and often defamed many of their own countrymen. Heroes, like the warrior Egil in Egil’s Saga, won fame by defeating such tormentors.  While some noble warrior kings, as Hrolfr Kraki, used Berzerkers as personal warriors of their territories. 

In art and in the Sagas, Berzerkers are often identified by the biting down of one’s shield. The act of biting into the shield was a display of unreasonable fury and anger of raving madness.