INS and type 2 diabetes mellitus: Glucose intolerance in geriatric monkeys, indicated by elevated blood glucose levels up to 30 minutes after glucose loading and the lack of insulin response to bolus IVGTT, is consistent with the age‐dependent increase in glucose intolerance and T2D in humans.5, 19 Although the geriatric males enrolled in this study were all wild‐caught, they had been housed at the facility for at least 4 years.