Age determination of the Iriomote cat by using cementum annuli

Abstract

AbstractWe estimated the age of Iriomote cats Prionailurus bengalensis iriomotensis by using their canine cementum annuli. By studying the month of death and staining condition of the outermost layer, we determined that the dark‐stained cementum lines of canines become apparent from February to September in males. By the time of deciduous tooth replacement and closure of the apical foramen, we estimated that the first prominent dark‐stained line is formed during the second winter and third spring of the cat's life. Examination of known‐age cats confirmed that the dark‐stained lines represent annual rings. Therefore, assuming that Iriomote cats are born in April, their age can be estimated by adding one to the number of dark‐stained lines. The month of death and number of dark‐stained cementum lines must be considered for age determination. We also attempted to estimate the age of living Iriomote cats by examining the correlation between the level of wear and number of cementum annuli of the upper canines, and categorized the degree of tooth wear into seven classes. Teeth that exhibited more extensive wear (i.e. in a higher wear class) had more cementum annuli. We defined three age categories for living cats based on canine wear characteristics: 1 year (wear level I), 2–6 years (wear levels II–V) and >7 years (wear levels VI–VII). Therefore, canine wear is the most effective index for age estimation of living Iriomote cats.