Thirteen tooth eruption stages and their corresponding chronological ages are descri bed from a series of giraffe jaws. These can be used for age determination in giraffes with immature dentition. Significant correlations of the lingual crown height (r=0-957; P < 0001) and lingual occlusal surface width (r=0-959; P < 0001) with the number of dark staining incremental lines in the cementum of thin decalcified sections of the maxillary first molar were found. The regression equations derived from these relationships provide a further method for determining the age of a giraffe. A composite plate showing maxillary first molar wear patterns provides a means of roughly assigning an age to a particular specimen. Thin sections of undecalcified teeth, mandible measurements, various other indices of tooth wear and eye lens mass were investigated and found unsuitable for age determination in this