The analysis of ratios of carbon-13 to carbon-12 along the length of a single elephant hair led Cerling and his crew to understand the elephants' diet. During the wet season, after the grass had grown long enough for elephants to grab with their trunks, their tail hair showed the presence of different form of carbon, indicating a high amount of high-protein grass. On the other hand, during the dry season, the results obtained by the analysis of the hair pointed out how elephants had switched over to shrubs and trees.