Figure 3

Mean (dots) and standard deviation (bars) carbon and nitrogen isotopic values in bone-collagen for Inia geoffrensis (Igeo), I. araguaiaensis (Iarag) and Trichechus inunguis (Tinung). Species showed significant differences in δ15N values but did not differ in δ13C values. Specimens were collected along the Amazon lowland (AL), and Amazon Estuary and adjacent coastal zone (AE) in Northern Brazil. Species drawings are not to scale.