1 INTRODUCTION The presence of growth layer lines in (or on) dental hard tissues is routinely exploited by zoologists and zooarchaeologists to determine age at death in individual wild mammals (Scheffer, 1950; Laws, 1952, 1953; Sergeant, 1959; Sergeant & Pimlott, 1959; Mansfield & Fisher, 1960; Low & Cowan, 1963; Mitchell, 1963, 1967; Ransom, 1966; Klevezal & Kleinenberg, 1967; Reimers & Nordby, 1968; Miller, 1974; Leader-Williams, 1979; Grue & Jensen, 1979; Perrin & Myrick, 1980).