This reduced but did not eliminate the possible confounds of place of birth, as we acknowledge epigenetic influences of early years of life in the wild may have persisting influences on metabolism.20 The age‐associated impairment in glucose‐stimulated insulin secretion has been well documented in other species and is likely associated with progressing pancreatic beta‐cell dysfunction.21, 22 A diminished glucose‐stimulated insulin secretion likely contributed to the impaired glucose tolerance in geriatric monkeys. Here, INS is linked to Impaired glucose tolerance.