BY THE SKIN OF YOUR TEETH

Linguists have traced this expression to a nomadic culture which for millenia has maintained itself on the fringes of the Arctic Circle.  Some anthropologists postulate that much like the Vulcan extra eyelid protected that humanoid species from the ultraviolet rays of their sun, paleolithic ancestors of our arctic race actually had evolved a layer of skin on their teeth to protect them from brain freeze.  Support for this theory is derived from cave drawings depicting a group of females engaged in various versions of what appears to be depilatory activity and one in particular is focused on the dental area. Corroborating evidence comes from forensic examination of uncovered adolescent remains which reveal traces in the enamel of a chemical molecularly similar to benzoil peroxide.


Extrapolations of these findings lead theorists to describe a scenario in which hunters, much like those forest animals who chew off a leg to escape from a trap, have sacrificed their dental epidermis in order to escape the clutches of a wooly mammoth.  This occurence must have been frequent enough to create a demand for replacements because recently deciphered tablets of law include proscription against trade deals.  There is some speculation that this may have led to blackmarket acitivity, especially among their urban population.  If once accepts the basic premise, the native american custom of scalp collecting may possibly be linked to their migration across the Bering Strait.