Trepanning

According to a new hypothesis,
The origin of poetry can be
Pegged to the first use of trepanation.

Of course, earlier examples are found
Every few years, it seems like, so no one
Can be wholly confident of the date,

Nonetheless, the oldest examples yet
Do establish a ceiling for the start
Of versifying, which can’t be any

Later than perforated crania,
Since, according to this hypothesis,
Skulls are only drilled when necessary,

And it’s well-known people need poetry
Like they need another hole in the head.