I wish I'd bookmarked this passage to quote in Barbarians:
"The barbarians wore only skins of mammoths and polar bears, along with boiled leather with plates of seal bone sewn onto it, and, instead of helmets, they used the skulls of animals from the Desolate Lands, which gave them a rather terrifying appearance. They were armed with axes and clubs, because they knew almost nothing of about bows and arrows. In battle they often went completely berserk."
- Alexey Pehov, Shadow Blizzard
Still, nice. I'm doubly glad I made sure to include skull helmets in Barbarians (page 29).