“…The tusks erupt later, primarily in males, but occasionally in females ( Marsh, 1980 ). The tusks are the only teeth present throughout life, and so have been used for age estimation ( Marsh, 1980 ; Mitchell, 1976 ; Read, Hohn & Lockyer, 2018 ) through counts of dentin growth layer groups (GLGs). The technique was first described by Scheffer in 1970 ( Scheffer, 1970 ) and is now broadly accepted for age estimation of dugongs ( Adulyanukosol, Amorena & Miyazaki, 1998 ; Kasuya & Nishiwaki, 1978 ; Marsh, 1980 ; Mitchell, 1976 ; Mitchell, 1978 ; Read, Hohn & Lockyer, 2018 ; Scheffer, 1970 ).…”