Pl. berserker. [Who wears a] bear “shirt”, exact synonym of ûfhedinn:[who wears] wolf fur. Snorri Sturluson who sees in ber an idea of nudity and concludes that the berserkir went "shirtless" is probably wrong.
Warriors.
The berserkir are those wild or furious warriors who, under certain circumstances, enter a trance and are then capable of incredible feats, while becoming invulnerable to fire and iron. Various representations and numerous allusions in skaldic poetry (9th century) prove that this image is ancient. It is part of the Odinic tradition:Ôdinn, god-shaman, is also god of ecstasy (poetic, sexual, magic and warrior). Berserkir may be traced back to masked Odinic brotherhoods (attested as early as 1800 BC).
These characters play an important role in the sagas where they are sometimes members of the chief's guard, sometimes a sort of rather ridiculous thugs (this aspect will be exploited with great verve by the Icelandic novelist Halldôr Laxness in The Saga of proud-to-arms, 1952). If we retain the meaning ùlfhedinn, "wolf-fur", we then join the idea of werewolf (lycanthrope) which was current throughout ancient Europe.