Úlfhéðnar are mentioned in Vatnsdœla saga, Haraldskvæði and the Völsunga saga. The Ulfhednar were said to wear the pelt of a wolf upon their heads when they entered battle, similar to the berserkers use of bear pelts.
The PERFECT picture to describe how I feel of late. I feel like I have a powerful inner beast that is caged and wishing to take back its personal power. A lot of us feel like this and I think it's important to start learning to love the beast in you.