The etymology of the term *berserk* is disputed. It may mean:
"*bare*-sark," as in "bare of shirt" and refer to the berserker's habit of going into battle unarmoured, or often, completely naked. Ynglingasaga records this tradition, saying of the warriors of Odhinn that "they went without coats of mail, and acted like mad dogs and wolves" (Snorri Sturluson. Heimskringla: History of the Kings of Norway. trans. Lee M. Holander. Austin: U of Texas P. 1964. p.10).
Others have contended that the term should be read "*bear*-sark," and describes the animal-skin garb of ther berserker. Grettirs Saga calls King Harald's berserkers "Wolf-Skins," and in King Harald's Saga they are called *ulfhedinn* or "wolf-coats," a term which appears in Vatnsdoela Saga and Hrafnsmal (Hilda R. Ellis-Davidson,"Shape-Changing in the Old Norse Sagas, " in Animals in Folklore. eds. J.R. Porter and W.M.S. Russell. Totowa NJ: Rowman and Littlefield. 1978. pp. 132-133), as well as in Grettirs Saga (Denton Fox and Hermann Palsson, trans. Grettir's Saga." Toronto: U of Toronto P. 1961. p. 3).
Some berserks also took names with björn or biôrn in them in reference to a bear. This is likely to be the source of names such as Beowulf and Bödvar Bjarki.
Excerpts taken from “Berserks: A History of Indo-European "Mad Warriors" by Michael P. Speidel
