Together, our integrative single-cell study indicates that Jamaican fruit bats evolved many diabetic-like features to deal with their diets but evolved protective mechanisms that prevent disease, such as upregulation of KLK1 in type A intercalated cells in the kidney, which protects against diabetic tissue damage74, and downregulation of IRS1 in beta cells in the pancreas, which causes hyperinsulinism but not diabetes144. The gene discussed is IRS1; the disease is hyperinsulinism.