(WAS:Inside the Modern Horses Mouth - Dental Wear
Fossil samples dating back as far as 55 million years ago can help us determine how long horses (on average) lived. 55 million years ago the average longevity of the hyracotherium was 5 years of age. 20 million years ago during the Miocene, analysis indicates longevity of up to 15 years. 10 million yeas ago during the Pliocene period Equus population was thought to live up to 25 years.
The Equestrian Triadan Numbering System
When using the Triadan classification for identifying individual teeth the horses' mouth is split into 4 arcades.
Each arcade has up to 11 teeth.