Researchers developed the first documented age classification method for free-ranging nilgai antelope by analyzing tooth eruption patterns, wear, and cementum annuli from 225 harvested nilgai in southern Texas. While the study found only weak correlations between tooth height measurements and age, it successfully established 13 tooth eruption stages and six age classes that can help land managers assess population structures and potentially evaluate age-biased predation in both Texas and the nilgai’s native Indian range.