Talk about being “long in the tooth”!

artic

The narwhal tusk can be up to 18 feet in length!!  It is formed from a modified left upper incisor tooth. Tusks
usually occur on males only, rarely there are
double tusks on one male. The tusk consists of an outer cementum layer
and one inside dentine layer. Inside the dentine is a pulp cavity that
extends down most of the length of the tusk, narrowing in diameter and
finally disappearing towards the tip of the tusk. That would be one hard root canal!

Narwhal Tusk – Monodon monoceros